出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2019/06/07 01:21:25」(JST)
| Childbirth | |
|---|---|
| Other names | Labour and delivery, partus, parturition, birth, confinement[1][2] |
| Newborn baby and mother | |
| Specialty | Obstetrics, midwifery |
| Complications | Obstructed labour, postpartum bleeding, eclampsia, postpartum infection, birth asphyxia, neonatal hypothermia[3][4][5] |
| Types | Vaginal delivery, C-section[6][7] |
| Causes | Pregnancy |
| Prevention | Birth control, abortion |
| Frequency | 135 million (2015)[8] |
| Deaths | 500,000 maternal deaths a year |
Childbirth, also known as labour and delivery, is the ending of a pregnancy by one or more babies leaving a woman's uterus by vaginal passage or Caesarean section.[7] In 2015, there were about 135 million births globally.[8] About 15 million were born before 37 weeks of gestation,[9] while between 3 and 12% were born after 42 weeks.[10] In the developed world most deliveries occur in hospitals,[11][12] while in the developing world most births take place at home with the support of a traditional birth attendant.[13]
The most common way of childbirth is a vaginal delivery.[6] It involves three stages of labour: the shortening and opening of the cervix, descent and birth of the baby, and the delivery of the placenta.[14] The first stage typically lasts twelve to nineteen hours, the second stage twenty minutes to two hours, and the third stage five to thirty minutes.[15] The first stage begins with crampy abdominal or back pains that last around half a minute and occur every ten to thirty minutes.[14] The crampy pains become stronger and closer together over time.[15] During the second stage pushing with contractions may occur.[15] In the third stage delayed clamping of the umbilical cord is generally recommended.[16] A number of methods can help with pain such as relaxation techniques, opioids, and spinal blocks.[15]
Most babies are born head first; however about 4% are born feet or buttock first, known as breech.[15][17] Typically the heads enter the pelvis facing to one side, and then rotate to face down.[18] During labour a woman can generally eat and move around as she likes, but pushing is not recommended during the first stage or during delivery of the head, and enemas are not recommended.[19] While making a cut to the opening of the vagina, known as an episiotomy, is common, it is generally not needed.[15] In 2012, about 23 million deliveries occurred by a surgical procedure known as Caesarean section.[20] Caesarean sections may be recommended for twins, signs of distress in the baby, or breech position.[15] This method of delivery can take longer to heal from.[15]
Each year, complications from pregnancy and childbirth result in about 500,000 maternal deaths, 7 million women have serious long term problems, and 50 million women have negative health outcomes following delivery.[5] Most of these occur in the developing world.[5] Specific complications include obstructed labour, postpartum bleeding, eclampsia, and postpartum infection.[5] Complications in the baby may include lack of oxygen at birth, birth trauma, prematurity, and infections.[4][21]
The most prominent sign of labour is strong repetitive uterine contractions. The distress levels reported by labouring women vary widely. They appear to be influenced by fear and anxiety levels, experience with prior childbirth, cultural ideas of childbirth and pain,[22][23] mobility during labour, and the support received during labour. Personal expectations, the amount of support from caregivers, quality of the caregiver-patient relationship, and involvement in decision-making are more important in women's overall satisfaction with the experience of childbirth than are other factors such as age, socioeconomic status, ethnicity, preparation, physical environment, pain, immobility, or medical interventions.[24]
Pain in contractions has been described as feeling similar to very strong menstrual cramps. Women are often encouraged to refrain from screaming, but moaning and grunting may be encouraged to help lessen pain. Crowning may be experienced as an intense stretching and burning. Even women who show little reaction to labour pains, in comparison to other women, show a substantially severe reaction to crowning.
Back labour is a term for specific pain occurring in the lower back, just above the tailbone, during childbirth.[25]
During the later stages of gestation there is an increase in abundance of oxytocin, a hormone that is known to evoke feelings of contentment, reductions in anxiety, and feelings of calmness and security around the mate.[26] Oxytocin is further released during labour when the fetus stimulates the cervix and vagina, and it is believed that it plays a major role in the bonding of a mother to her infant and in the establishment of maternal behavior. The act of nursing a child also causes a release of oxytocin.[27]
Between 70% and 80% of mothers in the United States report some feelings of sadness or "baby blues" after giving birth. The symptoms normally occur for a few minutes up to few hours each day and they should lessen and disappear within two weeks after delivery. Postpartum depression may develop in some women; about 10% of mothers in the United States are diagnosed with this condition. Preventive group therapy has proven effective as a prophylactic treatment for postpartum depression.[28][29]
Humans are bipedal with an erect stance. The erect posture causes the weight of the abdominal contents to thrust on the pelvic floor, a complex structure which must not only support this weight but allow, in women, three channels to pass through it: the urethra, the vagina and the rectum. The infant's head and shoulders must go through a specific sequence of maneuvers in order to pass through the ring of the mother's pelvis.
Six phases of a typical vertex or cephalic (head-first presentation) delivery:
The vagina is called a 'birth canal' when the baby enters this passage.
Station refers to the relationship of the fetal presenting part to the level of the ischial spines. When the presenting part is at the ischial spines the station is 0 (synonymous with engagement). If the presenting fetal part is above the spines, the distance is measured and described as minus stations, which range from −1 to −4 cm. If the presenting part is below the ischial spines, the distance is stated as plus stations ( +1 to +4 cm). At +3 and +4 the presenting part is at the perineum and can be seen.[30]
The fetal head may temporarily change shape substantially (becoming more elongated) as it moves through the birth canal. This change in the shape of the fetal head is called molding and is much more prominent in women having their first vaginal delivery.[31]
Cervical ripening is a term used to describe the physical and chemical changes in the cervix to prepare it for the stretching that will take place as the fetus moves out of the uterus and into the birth canal. A scoring system called a Bishop score can be used to judge the degree of cervical ripening in order to predict the timing of labor and delivery of the infant or for women at risk for preterm labor. It is also used to judge when a woman will respond to induction of labor for a postdate pregnancy or other medical reasons. There are several methods of inducing cervical ripening which will allow the uterine contractions to effectively dilate the cervix.[32]
There are various definitions of the onset of labour, including:
In order to avail for more uniform terminology, the first stage of labour is divided into "latent" and "active" phases, where the latent phase is sometimes included in the definition of labour,[36] and sometimes not.[37]
Common signs that labour, commonly spelled as labor, is about to begin may include "lightening". Lightening describes the baby moving down from the rib cage with the head of the baby engaging deep in the pelvis. The pregnant woman may then find breathing easier since her lungs have more room for expansion, but pressure on her bladder may cause more frequent need to void (urinate). Lightening may occur a few weeks or a few hours before labour begins, or even not until labour has begun.[38]
Some women also experience an increase in vaginal discharge several days before labour begins when the "mucus plug", a thick plug of mucus that blocks the opening to the uterus, is pushed out into the vagina. The mucus plug may become dislodged days before labour begins or not until the start of labour.[38]
While living inside the uterus the baby is enclosed in a fluid-filled membrane called the amniotic sac. Shortly before, at the beginning of, or during labor the sac ruptures. Once the sac ruptures, termed "the water breaks", the baby is at risk for infection and the mother's medical team will assess the need to induce labor if it has not started within the time they believe to be safe for the infant.[38]
Many women are known to experience what has been termed the "nesting instinct". Women report a spurt of energy shortly before going into labour.[38]
Folklore has long held that most babies are born in the late night or very early morning and recent (2018) research has found this to be correct in the U.S., but only for babies born at home or on Saturday or Sunday. All other births are most likely to occur between 8 a.m. and noon, a reflection of the fact that planned C-sections are generally scheduled for 8 a.m. Likewise, births from induced deliveries rose during the morning hours and peaked at 3 p.m. The most likely day of the week for a baby's birthday in the U.S. is Monday, followed by Tuesday, likely related to scheduled deliveries as well.[39][40]
The latent phase is generally defined as beginning at the point at which the woman perceives regular uterine contractions.[41] In contrast, Braxton Hicks contractions, which are contractions that may start around 26 weeks gestation and are sometimes called "false labour", are infrequent, irregular, and involve only mild cramping.[42]
Cervical effacement, which is the thinning and stretching of the cervix, and cervical dilation occur during the closing weeks of pregnancy. Effacement is usually complete or near complete and dilation is about 5 cm by the end of the latent phase.[43] The degree of cervical effacement and dilation may be felt during a vaginal examination. The latent phase ends with the onset of the active first stage.
The active stage of labour (or "active phase of first stage" if the previous phase is termed "latent phase of first stage") has geographically differing definitions. The World Health Organization describes the active first stage as "a period of time characterized by regular painful uterine contractions, a substantial degree of cervical effacement and more rapid cervical dilatation from 5 cm until full dilatation for first and subsequent labours.[44] In the US, the definition of active labour was changed from 3 to 4 cm, to 5 cm of cervical dilation for multiparous women, mothers who had given birth previously, and at 6 cm for nulliparous women, those who had not given birth before.[45] This was done in an effort to increase the rates of vaginal delivery.[46]
Health care providers may assess a labouring mother's progress in labour by performing a cervical exam to evaluate the cervical dilation, effacement, and station. These factors form the Bishop score. The Bishop score can also be used as a means to predict the success of an induction of labour.
During effacement, the cervix becomes incorporated into the lower segment of the uterus. During a contraction, uterine muscles contract causing shortening of the upper segment and drawing upwards of the lower segment, in a gradual expulsive motion.[citation needed] The presenting fetal part then is permitted to descend. Full dilation is reached when the cervix has widened enough to allow passage of the baby's head, around 10 cm dilation for a term baby.
A standard duration of the latent first stage has not been established and can vary widely from one woman to another. However, the duration of active first stage (from 5 cm until full cervical dilatation) usually does not extend beyond 12 hours in first labours ("primiparae"), and usually does not extend beyond 10 hours in subsequent labours ("multiparae"). The median duration of active first stage is 4 hours in first labours and 3 hours in second and
subsequent labours.[47]
Dystocia of labor, also termed dysfunctional labor or failure to progress, is defined as difficult labor or abnormally slow progress of labor. The term is used to describe a lack of progressive cervical dilatation or lack of descent of the fetus. Friedman's Curve, developed in 1955, was for many years used to determine labor dystocia. However, more recent medical research suggests that the Friedman curve may not be currently applicable.[48][49]
The expulsion stage begins when the cervix is fully dilated, and ends when the baby is born. As pressure on the cervix increases, women may have the sensation of pelvic pressure and an urge to begin pushing. At the beginning of the normal second stage, the head is fully engaged in the pelvis; the widest diameter of the head has passed below the level of the pelvic inlet. The fetal head then continues descent into the pelvis, below the pubic arch and out through the vaginal introitus (opening). This is assisted by the additional maternal efforts of "bearing down" or pushing. The appearance of the fetal head at the vaginal orifice is termed the "crowning". At this point, the woman will feel an intense burning or stinging sensation.
When the amniotic sac has not ruptured during labour or pushing, the infant can be born with the membranes intact. This is referred to as "delivery en caul".
Complete expulsion of the baby signals the successful completion of the second stage of labour.
The second stage varies from one woman to another. In first labours, birth is usually completed within 3 hours whereas in subsequent
labours, birth is usually completed within 2 hours.[50] Labours longer than 3 hours are associated with declining rates of spontaneous vaginal delivery and increasing rates of infection, perineal tears, and obstetric hemorrhage, as well as the need for intensive care of the neonate.[51]
The period from just after the fetus is expelled until just after the placenta is expelled is called the third stage of labour or the involution stage. Placental expulsion begins as a physiological separation from the wall of the uterus. The average time from delivery of the baby until complete expulsion of the placenta is estimated to be 10–12 minutes dependent on whether active or expectant management is employed.[52] In as many as 3% of all vaginal deliveries, the duration of the third stage is longer than 30 minutes and raises concern for retained placenta.[53]
Placental expulsion can be managed actively or it can be managed expectantly, allowing the placenta to be expelled without medical assistance. Active management is described as the administration of a uterotonic drug within one minute of fetal delivery, controlled traction of the umbilical cord and fundal massage after delivery of the placenta, followed by performance of uterine massage every 15 minutes for two hours.[54] In a joint statement, World Health Organization, the International Federation of Gynaecology and Obstetrics and the International Confederation of Midwives recommend active management of the third stage of labour in all vaginal deliveries to help to prevent postpartum hemorrhage.[55][56][57]
Delaying the clamping of the umbilical cord for at least one minute or until it ceases to pulsate, which may take several minutes, improves outcomes as long as there is the ability to treat jaundice if it occurs. For many years it was believed that late cord cutting led to a mother's risk of experiencing significant bleeding after giving birth, called postpartum bleeding. However a recent review found that delayed cord cutting in healthy full-term infants resulted in early haemoglobin concentration and higher birthweight and increased iron reserves up to six months after birth with no change in the rate of postpartum bleeding.[58][59]
The "fourth stage of labour" is the period beginning immediately after the birth of a child and extending for about six weeks. The terms postpartum and postnatal are often used to describe this period.[60] The woman's body, including hormone levels and uterus size, return to a non-pregnant state and the newborn adjusts to life outside the mother's body. The World Health Organization (WHO) describes the postnatal period as the most critical and yet the most neglected phase in the lives of mothers and babies; most deaths occur during the postnatal period.[61]
Following the birth, if the mother had an episiotomy or a tearing of the perineum, it is stitched. The mother has regular assessments for uterine contraction and fundal height,[62] vaginal bleeding, heart rate and blood pressure, and temperature, for the first 24 hours after birth. The first passing of urine should be documented within 6 hours.[61] Afterpains (pains similar to menstrual cramps), contractions of the uterus to prevent excessive blood flow, continue for several days. Vaginal discharge, termed "lochia", can be expected to continue for several weeks; initially bright red, it gradually becomes pink, changing to brown, and finally to yellow or white.[63] Some women experience an uncontrolled episode of shivering or postpartum chills, after the birth.
Most authorities suggest the infant be placed in skin-to-skin contact with the mother for 1–2 hours immediately after birth, putting routine cares off until later.
Until recently babies born in hospitals were removed from their mothers shortly after birth and brought to the mother only at feeding times. Mothers were told that their newborn would be safer in the nursery and that the separation would offer the mother more time to rest. As attitudes began to change, some hospitals offered a "rooming in" option wherein after a period of routine hospital procedures and observation, the infant could be allowed to share the mother's room. However, more recent information has begun to question the standard practice of removing the newborn immediately postpartum for routine postnatal procedures before being returned to the mother. Beginning around 2000, some authorities began to suggest that early skin-to-skin contact (placing the naked baby on the mother's chest) may benefit both mother and infant. Using animal studies that have shown that the intimate contact inherent in skin-to-skin contact promotes neurobehaviors that result in the fulfillment of basic biological needs as a model, recent studies have been done to assess what, if any, advantages may be associated with early skin-to-skin contact for human mothers and their babies. A 2011 medical review looked at existing studies and found that early skin-to-skin contact, sometimes called kangaroo care, resulted in improved breastfeeding outcomes, cardio-respiratory stability, and a decrease in infant crying.[64][65] A 2016 Cochrane review found that skin-to-skin contact at birth promotes the likelihood and effectiveness of breastfeeding.[66]
As of 2014, early postpartum skin-to-skin contact is endorsed by all major organizations that are responsible for the well-being of infants, including the American Academy of Pediatrics.[67] The World Health Organization (WHO) states that "the process of
childbirth is not finished until the baby has safely transferred from placental to mammary nutrition." They advise that the newborn be placed skin-to-skin with the mother, postponing any routine procedures for at least one to two hours. The WHO suggests that any initial observations of the infant can be done while the infant remains close to the mother, saying that even a brief separation before the baby has had its first feed can disturb the bonding process. They further advise frequent skin-to-skin contact as much as possible during the first days after delivery, especially if it was interrupted for some reason after the delivery.[68] The National Institute for Health and Care Excellence also advises postponing procedures such as weighing, measuring, and bathing for at least 1 hour to insure an initial period of skin-to-skin contact between mother and infant.[69]
In many cases and with increasing frequency, childbirth is achieved through induction of labour or caesarean section. Caesarean section is the removal of the neonate through a surgical incision in the abdomen, rather than through vaginal birth.[70] Childbirth by C-Sections increased 50% in the U.S. from 1996 to 2006. In 2011, 32.8% of births in the U.S. were delivered by cesarean section.[70] Induced births and elective cesarean before 39 weeks can be harmful to the neonate as well as harmful or without benefit to the mother. Therefore, many guidelines recommend against non-medically required induced births and elective cesarean before 39 weeks.[71] The 2012 rate of labour induction in the United States was 23.3%, and has more than doubled from 1990 to 2010.[72][73] Pitocin is commonly used to induce uterine contractions. A large review of methods of induction was published in 2011.[74]
The American Congress of Obstetricians and Gynecologists (ACOG) guidelines recommend a full evaluation of the maternal-fetal status, the status of the cervix, and at least a 39 completed weeks (full term) of gestation for optimal health of the newborn when considering elective induction of labour. Per these guidelines, the following conditions may be an indication for induction, including:
Induction is also considered for logistical reasons, such as the distance from hospital or psychosocial conditions, but in these instances gestational age confirmation must be done, and the maturity of the fetal lung must be confirmed by testing. The ACOG also note that contraindications for induced labour are the same as for spontaneous vaginal delivery, including vasa previa, complete placenta praevia, umbilical cord prolapse or active genital herpes simplex infection.[75]
Deliveries are assisted by a number of professionals including: obstetricians, family physicians and midwives. For low risk pregnancies all three result in similar outcomes.[76]
Eating or drinking during labour is an area of ongoing debate. While some have argued that eating in labour has no harmful effects on outcomes,[77] others continue to have concern regarding the increased possibility of an aspiration event (choking on recently eaten foods) in the event of an emergency delivery due to the increased relaxation of the esophagus in pregnancy, upward pressure of the uterus on the stomach, and the possibility of general anesthetic in the event of an emergency cesarean.[78] A 2013 Cochrane review found that with good obstetrical anaesthesia there is no change in harms from allowing eating and drinking during labour in those who are unlikely to need surgery. They additionally acknowledge that not eating does not mean there is an empty stomach or that its contents are not as acidic. They therefore conclude that "women should be free to eat and drink in labour, or not, as they wish."[79]
At one time shaving of the area around the vagina, was common practice due to the belief that hair removal reduced the risk of infection, made an episiotomy (a surgical cut to enlarge the vaginal entrance) easier, and helped with instrumental deliveries. It is currently less common, though it is still a routine procedure in some countries even though a systematic review found no evidence to recommend shaving.[80] Side effects appear later, including irritation, redness, and multiple superficial scratches from the razor. Another effort to prevent infection has been the use of the antiseptic chlorhexidine or providone-iodine solution in the vagina. Evidence of benefit with chlorhexidine is lacking.[81] A decreased risk is found with providone-iodine when a cesarean section is to be performed.[82]
In 2013 a review of the effectiveness of active management for reducing caesarean section rates in low-risk women was carried out. Active management of labour consists of a number of care principles, including "strict diagnosis of labour", routine artificial rupture of membranes, oxytocin for slow progress, and one-to-one support. The review reported that when compared to routine care there were no differences in the use of medications for pain, maternal or neonatal complications, or rates of assisted vaginal deliveries. There was a slight reduction in the caesarean section rate, however active management was seen as "highly prescriptive and interventional."[83]
The World Health Organization advises: "Avoid the systematic use of a package of interventions ("active management of labour") to prevent possible labour delay because it is highly prescriptive and can undermine women’s choices and autonomy during care."[84]
Some women prefer to avoid analgesic medication during childbirth. Psychological preparation may be beneficial. Relaxation techniques, immersion in water, massage, and acupuncture may provide pain relief. Acupuncture and relaxation were found to decrease the number of caesarean sections required.[85] Immersion in water has been found to relieve pain during the first stage of labor and to reduce the need for anesthesia and shorten the duration of labor, however the safety and efficacy of immersion during birth, water birth, has not been established or associated with maternal or fetal benefit.[86]
Most women like to have someone to support them during labour and birth; such as a midwife, nurse, or doula; or a lay person such as the father of the baby, a family member, or a close friend. Studies have found that continuous support during labor and delivery reduce the need for medication and a caesarean or operative vaginal delivery, and result in an improved Apgar score for the infant[87][88]
Different measures for pain control have varying degrees of success and side effects to the woman and her baby. In some countries of Europe, doctors commonly prescribe inhaled nitrous oxide gas for pain control, especially as 53% nitrous oxide, 47% oxygen, known as Entonox; in the UK, midwives may use this gas without a doctor's prescription.[citation needed] Opioids such as fentanyl may be used, but if given too close to birth there is a risk of respiratory depression in the infant.[citation needed]
Popular medical pain control in hospitals include the regional anesthetics epidurals (EDA), and spinal anaesthesia. Epidural analgesia is a generally safe and effective method of relieving pain in labour, but is associated with longer labour, more operative intervention (particularly instrument delivery), and increases in cost.[89] However, a recent Cochrane review suggests that the new epidural techniques have no more effect on labour time and the used instruments.[90] Generally, pain and stress hormones rise throughout labour for women without epidurals, while pain, fear, and stress hormones decrease upon administration of epidural analgesia, but rise again later.[91]
Medicine administered via epidural can cross the placenta and enter the bloodstream of the fetus.[92] Epidural analgesia has no statistically significant impact on the risk of caesarean section, and does not appear to have an immediate effect on neonatal status as determined by Apgar scores.[90]
Augmentation is the process of stimulating the uterus to increase the intensity and duration of contractions after labour has begun. Several methods of augmentation are commonly been used to treat slow progress of labour (dystocia) when uterine contractions are assessed to be too weak. Oxytocin is the most common method used to increase the rate of vaginal delivery.[93] The World Health Organization recommends its use either alone or with amniotomy (rupture of the amniotic membrane) but advises that it must be used only after it has been correctly confirmed that labour is not proceeding properly if harm is to be avoided. The WHO does not recommend the use of antispasmodic agents for prevention of delay in labour.[94]
Perineal tears can occur during childbirth, most often at the vaginal opening as the baby's head passes through, especially if the baby descends quickly. Tears can involve the perineal skin or extend to the muscles and the anal sphincter and anus. While making a cut to the opening of the vagina, known as an episiotomy is common, it is generally not needed.[15] When needed, the midwife or obstetrician makes a surgical cut in the perineum to prevent severe tears that can be difficult to repair. A 2017 Cochrane review compared episiotomy as needed (restrictive) with routine episiotomy to determine the possible benefits and harms for mother and baby. The review found that restrictive episiotomy policies appeared to give a number of benefits compared with using routine episiotomy. Women experienced less severe perineal trauma, less posterior perineal trauma, less suturing and fewer healing complications at seven days with no difference in occurrence of pain, urinary incontinence, painful sex or severe vaginal/perineal trauma after birth.[95]
Obstetric forceps or ventouse may be used to facilitate childbirth.
In cases of a head first-presenting first twin, twins can often be delivered vaginally. In some cases twin delivery is done in a larger delivery room or in an operating theatre, in the event of complication e.g.
Obstetric care frequently subjects women to institutional routines, which may have adverse effects on the progress of labour. Supportive care during labour may involve emotional support, comfort measures, and information and advocacy which may promote the physical process of labour as well as women's feelings of control and competence, thus reducing the need for obstetric intervention. The continuous support may be provided either by hospital staff such as nurses or midwives, doulas, or by companions of the woman's choice from her social network. There is increasing evidence to show that the participation of the child's father in the birth leads to better birth and also post-birth outcomes, providing the father does not exhibit excessive anxiety.[96]
A recent Cochrane review involving more than 15,000 women in a wide range of settings and circumstances found that "Women who received continuous labour support were more likely to give birth 'spontaneously', i.e. give birth with neither caesarean nor vacuum nor forceps. In addition, women were less likely to use pain medications, were more likely to be satisfied, and had slightly shorter labours. Their babies were less likely to have low five-minute Apgar scores."[97][needs update]
For monitoring of the fetus during childbirth, a simple pinard stethoscope or doppler fetal monitor ("doptone") can be used. A method of external (noninvasive) fetal monitoring (EFM) during childbirth is cardiotocography, using a cardiotocograph that consists of two sensors: The heart (cardio) sensor is an ultrasonic sensor, similar to a Doppler fetal monitor, that continuously emits ultrasound and detects motion of the fetal heart by the characteristic of the reflected sound. The pressure-sensitive contraction transducer, called a tocodynamometer (toco) has a flat area that is fixated to the skin by a band around the belly. The pressure required to flatten a section of the wall correlates with the internal pressure, thereby providing an estimate of contraction.[98] Monitoring with a cardiotocograph can either be intermittent or continuous.[99] The World Health Organization (WHO) advises that for healthy women undergoing spontaneous labour continuous cardiotocography is not recommended for assessment of fetal well-being. The WHO states: "In countries and settings where continuous CTG is used defensively to protect against litigation, all stakeholders should be made aware that this practice is not evidence-based and does not improve birth outcomes."[100]
A mother's water has to break before internal (invasive) monitoring can be used. More invasive monitoring can involve a fetal scalp electrode to give an additional measure of fetal heart activity, and/or intrauterine pressure catheter (IUPC). It can also involve fetal scalp pH testing.
Per figures retrieved in 2015, since 1990 there has been a 44 per cent decline in the maternal death rate. However, according to 2015 figures 830 women die every day from causes related to pregnancy or childbirth and for every woman who dies, 20 or 30 encounter injuries, infections or disabilities. Most of these deaths and injuries are preventable.[102][103]
In 2008, noting that each year more than 100,000 women die of complications of pregnancy and childbirth and at least 7 million experience serious health problems while 50 million more have adverse health consequences after childbirth, the World Health Organization (WHO) has urged midwife training to strengthen maternal and newborn health services. To support the upgrading of midwifery skills the WHO established a midwife training program, Action for Safe Motherhood.[5]
The rising maternal death rate in the U.S. is of concern. In 1990 the U.S. ranked 12th of the 14 developed countries that were analyzed. However, since that time the rates of every country have steadily continued to improve while the U.S. rate has spiked dramatically. While every other developed nation of the 14 analyzed in 1990 shows a 2017 death rate of less than 10 deaths per every 100,000 live births, the U.S. rate has risen to 26.4. By comparison, the United Kingdom ranks second highest at 9.2 and Finland is the safest at 3.8.[104] Furthermore, for every one of the 700 to 900 U.S. woman who die each year during pregnancy or childbirth, 70 experience significant complications such as hemorrhage and organ failure, totaling more than 1 percent of all births.[105]
Compared to other developed nations, the United States also has high infant mortality rates. The Trust for America's Health reports that as of 2011, about one third of American births have some complications; many are directly related to the mother's health including increasing rates of obesity, type 2 diabetes, and physical inactivity. The U.S. Centers for Disease Control and Prevention (CDC) has led an initiative to improve woman's health previous to conception in an effort to improve both neonatal and maternal death rates.[106]
The second stage of labour may be delayed or lengthy due to poor or uncoordinated uterine action, an abnormal uterine position such as breech or shoulder dystocia, and cephalopelvic disproportion (a small pelvis or large infant). Prolonged labour may result in maternal exhaustion, fetal distress, and other complications including obstetric fistula.[107]
Eclampsia is the onset of seizures (convulsions) in a woman with pre-eclampsia. Pre-eclampsia is a disorder of pregnancy in which there is high blood pressure and either large amounts of protein in the urine or other organ dysfunction. Pre-eclampsia is routinely screened for during prenatal care. Onset may be before, during, or rarely, after delivery. Around one percent of women with eclampsia die.
A puerperal disorder or postpartum disorder is a complication which presents primarily during the puerperium, or postpartum period. The postpartum period can be divided into three distinct stages; the initial or acute phase, 6–12 hours after childbirth; subacute postpartum period, which lasts 2–6 weeks, and the delayed postpartum period, which can last up to 6 months. In the subacute postpartum period, 87% to 94% of women report at least one health problem.[108][109] Long term health problems (persisting after the delayed postpartum period) are reported by 31% of women.[110]
Postpartum bleeding is the leading cause of death of birthing mothers in the world, especially in the developing world. Globally it occurs about 8.7 million times and results in 44,000 to 86,000 deaths per year. Uterine atony, the inability of the uterus to contract, is the most common cause of postpartum bleeding. Following delivery of the placenta, the uterus is left with a large area of open blood vessels which must be constricted to avoid blood loss. Retained placental tissue and infection may contribute to uterine atony. Heavy blood loss leads to hypovolemic shock, insufficient perfusion of vital organs and death if not rapidly treated.
Postpartum infections, also known as childbed fever and puerperal fever, are any bacterial infections of the reproductive tract following childbirth or miscarriage. Signs and symptoms usually include a fever greater than 38.0 °C (100.4 °F), chills, lower abdominal pain, and possibly bad-smelling vaginal discharge. The infection usually occurs after the first 24 hours and within the first ten days following delivery. Infection remains a major cause of maternal deaths and morbidity in the developing world. The work of Ignaz Semmelweis was seminal in the pathophysiology and treatment of childbed fever and his work saved many lives.
Childbirth can be an intense event and strong emotions, both positive and negative, can be brought to the surface. Abnormal and persistent fear of childbirth is known as tokophobia. The prevalence of fear of childbirth around the world ranges between 4-25%, with 3-7% of pregnant women having clinical fear of childbirth.[111][112]
Most new mothers may experience mild feelings of unhappiness and worry after giving birth. Babies require a lot of care, so it’s normal for mothers to be worried about, or tired from, providing that care. The feelings, often termed the "baby blues", affect up to 80 percent of mothers. They are somewhat mild, last a week or two, and usually go away on their own.[113]
Postpartum depression is different from the “baby blues”. With postpartum depression, feelings of sadness and anxiety can be extreme and might interfere with a woman’s ability to care for herself or her family. Because of the severity of the symptoms, postpartum depression usually requires treatment. The condition, which occurs in nearly 15 percent of births, may begin shortly before or any time after childbirth, but commonly begins between a week and a month after delivery.[113]
Childbirth-related posttraumatic stress disorder is a psychological disorder that can develop in women who have recently given birth.[114][115][116] Causes include issues such as an emergency C-section, preterm labour, inadequate care during labour,
lack of social support following childbirth, and others. Examples of symptoms include intrusive symptoms, flashbacks and nightmares, as well as symptoms of avoidance (including amnesia for the whole or parts of the event), problems in developing a mother-child attachment, and others similar to those commonly experienced in posttraumatic stress disorder (PTSD). Many women who are experiencing symptoms of PTSD after childbirth are misdiagnosed with postpartum depression or adjustment disorders. These diagnoses can lead to inadequate treatment.[117]
Postpartum psychosis is a rare psychiatric emergency in which symptoms of high mood and racing thoughts (mania), depression, severe confusion, loss of inhibition, paranoia, hallucinations and delusions set in, beginning suddenly in the first two weeks after childbirth. The symptoms vary and can change quickly.[118] It usually requires hospitalization. The most severe symptoms last from 2 to 12 weeks, and recovery takes 6 months to a year.[118]
Five causes make up about 80% of newborn deaths. They include prematurity and low-birth-weight, infections, lack of oxygen at birth, and trauma during birth.[21]
Preterm birth is the birth of an infant at fewer than 37 weeks gestational age. It is estimated that 1 in 10 babies are born prematurely. Premature birth is the leading cause of death in children under 5 years of age though many that survive experience disabilities including learning defects and visual and hearing problems. Causes for early birth may be unknown or may be related to certain chronic conditions such as diabetes, infections, and other known causes. The World Health Organization has developed guidelines with recommendations to improve the chances of survival and health outcomes for preterm infants.[119]
Newborns are prone to infection in the first month of life. The organism S. agalactiae (Group B Streptococcus) or (GBS) is most often the cause of these occasionally fatal infections. The baby contracts the infection from the mother during labor. In 2014 it was estimated that about one in 2000 newborn babies have GBS bacterial infections within the first week of life, usually evident as respiratory disease, general sepsis, or meningitis.[121]
Untreated sexually transmitted infections (STIs) are associated with congenital and infections in newborn babies, particularly in the areas where rates of infection remain high. The majority of STIs have no symptoms or only mild symptoms that may not be recognized. Mortality rates resulting from some infections may be high, for example the overall perinatal mortality rate associated with untreated syphilis is 30%.[122]
Perinatal asphyxia is the medical condition resulting from deprivation of oxygen to a newborn infant that lasts long enough during the birth process to cause physical harm, usually to the brain. Hypoxic damage can occur to most of the infant's organs (heart, lungs, liver, gut, kidneys), but brain damage is of most concern and perhaps the least likely to quickly or completely heal.[123][123]
Risk factors for fetal birth injury include fetal macrosomia (big baby), maternal obesity, the need for instrumental delivery, and an inexperienced attendant. Specific situations that can contribute to birth injury include breech presentation and shoulder dystocia. Most fetal birth injuries resolve without long term harm, but brachial plexus injury may lead to Erb's palsy or Klumpke's paralysis.[124]
The process of childbirth in Western society has evolved significantly over the years.
Historically women have been attended and supported by other women during labour and birth. Midwife training in European cities began in the 1400s, but rural women were usually assisted by female family or friends.[125] However, it was not simply a ladies' social bonding event as some historians have portrayed - fear and pain often filled the atmosphere, as death during childbirth was a common occurrence.[126] In the United States, before the 1950s the husband would not be in the birthing room. It did not matter if it was a home birth; the husband was waiting downstairs or in another room in the home. If it was in a hospital then the husband was in the waiting room.[127] Fathers were only permitted in the room if the life of the mother or baby was severely at-risk. In 1522, a German physician was sentenced to death for sneaking into a delivery room dressed as a woman.[125]
Ironically, the majority of guidebooks related to pregnancy and childbirth were written by men who had never been involved in the birthing process. A Greek physician, Soranus of Ephesus, wrote a book about obstetrics and gynecology in the second century, which was referenced for the next thousand years. The book contained endless home remedies for pregnancy and childbirth, many of which would be considered heinous by modern women and medical professionals.[125]
Historically, most women gave birth at home without emergency medical care available. In the early days of hospitalization of childbirth, a seventeenth century maternity ward in Paris was incredibly congested, with up to five pregnant women sharing one bed. At this hospital, one in five women died during the birthing process.[125] At the onset of the Industrial Revolution, giving birth at home became more difficult due to congested living spaces and dirty living conditions. This drove urban and lower class women to newly available hospitals, while wealthy and middle-class women continued to labor at home.[128] Consequently, wealthier women experienced poorer maternal mortality rates than those of a lower social class.[129]</ref> Throughout the 1900s there was an increasing availability of hospitals, and more women began going into the hospital for labor and delivery.[130] In the United States, 5% of women gave birth in hospitals in 1900. By 1930, 50% of all women and 75% of urban-dwelling women delivered in hospitals.[125] By 1960, this number increased to 96%.[126] By the 1970s, home birth rates fell to approximately 1%.[131] In the United States, the middle classes were especially receptive to the medicalization of childbirth, which promised a safer and less painful labor.[130]
Accompanied by the shift from home to hospital was the shift from midwife to physician. Male physicians began to replace female midwives in Europe and the United States in the 1700s. The rise in status and popularity of this new position was accompanied by a drop in status for midwives. By the 1800s, affluent families were primarily male doctors to assist with their deliveries, and female midwives were seen as a resource for women who couldn't afford better care. This completely removed women from assisting in labor, as only men were eligible to become doctors at the time. Additionally, it privatized the birthing process as family members and friends were often banned from the delivery room. There was opposition to this change from both progressive feminists and religious conservatives. The feminists were concerned about job security for a role that had traditionally been held by women. The conservatives argued that it was immoral for a women to be exposed in such a way in front of a man. For this reason, many male obstetricians performed deliveries in dark rooms or with their patient fully covered with a drape. As one author puts it, "since the 1920's, physicians have been the unchallenged birth attendants."[126]
The use of pain medication in labor has been a controversial issue for hundreds of years. A Scottish woman was burned at the stake in 1591 for requesting pain relief in the delivery of twins. Medication did become more acceptable in 1852, when Queen Victoria used chloroform as pain relief during labor. The use of morphine and scopolamine, also known as "twilight sleep," was first used in Germany and popularized by German physicians Bernard Kronig and Karl Gauss. This concoction offered minor pain relief but mostly allowed women to completely forget the entire delivery process. Under twilight sleep, mothers were often blindfolded and restrained as they experienced the immense pain of childbirth. The cocktail came with severe side effects, such as decreased uterine contractions and altered mental state. Additionally, babies delivered with the use of childbirth drugs often experienced temporarily-ceased breathing. The feminist movement in the United States openly and actively supported the use of twilight sleep, which was introduced to the country in 1914. Some physicians, many of whom had been using painkillers for the past fifty years, including opium, cocaine, and quinine, embraced the new drug. Others were rightfully hesitant.[125]
In the late sixteenth century, the Chamberlen family developed obstetric forceps for safely delivering babies in compromised positions. They kept this design a family secret for two hundred years. Before forceps, babies stuck in the birth canal almost always faced imminent death – the mother's life was typically spared at the expense of the baby. After many generations, a Chamberlen offspring decided to go public with the design. By the 1800s, midwives and doctors began using forceps, although with strong hesitation at first. In 1908, a Harvard-graduated OB/GYN, Franklin S. Newell, publicly recommended that forceps be used for upper class women, who he considered too physically and emotionally weak to naturally deliver a baby.[125] The use of tools and medication was highly encouraged for use in all deliveries by American physician Joseph Bolivar DeLee in the 1920s. This received major backlash from the medical community, with some claiming that DeLee's advice to use forceps when not medically necessary resulted in "many unnecessary deaths."[129]
While forceps have gone through periods of high popularity, today they are only used in approximately 10% of deliveries. The caesarean section (or C-section) has become the more popular solution for difficult deliveries. In 2005, one third of babies were born via C-section. Historically, surgical delivery was a last-resort method of extracting a baby from its deceased or dying mother. There are many conflicting stories of the first successful C-section in which both mom and baby survived. It is, however, known that the procedure had been attempted for hundreds of years before it became accepted in the beginning of the twentieth century.[125]
In some Western societies, caesarean section is becoming more commonplace as vaginal births are seen by some as more difficult and painful.[132] However, some also view them as stigmatized, or an undesirable alternative to "natural" birth, unassisted birth, and other non-surgical or less-interventionist approaches to birth.[133] Amish societies, for example, tend to place value on the strength of the women's bodies so that their natural, at home birth is seen as less daunting. Most women in Amish societies find the pain and effort of childbirth satisfactory.[132]
The re-emergence of "natural childbirth" began in Europe and was adopted by some in the U.S. as early as the late 1940s. Early supporters believed that the drugs used during deliveries interfered with "happy childbirth" and could negatively impact the newborn's "emotional wellbeing". By the 1970s, the call for natural childbirth was spread nationwide, in conjunction with the second-wave of the feminist movement.[125] While it is still most common for American women to deliver in the hospital, supporters of natural birth still widely exist, especially in the UK where midwife-assisted home births have gained popularity in recent years.[131]
Childbirth statistics in US before 1915 were not recorded but moving forward the US has had historically poor maternal mortality rates in comparison to other developed countries. There is more reliable data on maternal mortality from Britain from 1880 onward. Outcomes for mothers in childbirth were especially poor before 1930 due to high rates of puerperal fever.[129] Until germ theory was accepted in the mid-1800s, it was assumed that puerperal fever was either caused by a variety of sources, including the leakage of breast milk into the body and anxiety, rather than by a pathogen that was transmitted by the dirty hands and tools of doctors. This misconception was likely responsible for the high prevalence of puerperal fever.[125] The home-births facilitated by trained midwives produced the best outcomes from 1880 to 1930 in the U.S. and Europe, whereas physician-facilitated hospital births produced the worst. The change in trend of maternal mortality can be attributed with the widespread use of sulfonamides, along with the progression of medical technology, more extensive physician training, and less medical interference with normal deliveries.[129]
According to a 2013 analysis performed commissioned by the New York Times and performed by Truven Healthcare Analytics, the cost of childbirth varies dramatically by country. In the United States the average amount actually paid by insurance companies or other payers in 2012 averaged $9,775 for an uncomplicated conventional delivery and $15,041 for a caesarean birth.[134] The aggregate charges of healthcare facilities for 4 million annual births in the United States was estimated at over $50 billion. The summed cost of prenatal care, childbirth, and newborn care came to $30,000 for a vaginal delivery and $50,000 for a caesarian section.
In the United States, childbirth hospital stays have some of the lowest ICU utilizations. Vaginal delivery with and without complicating diagnoses and caesarean section with and without comorbidities or major comorbidities account for four of the fifteen types of hospital stays with low rates of ICU utilization (where less than 20% of visits were admitted to the ICU). During stays with ICU services, approximately 20% of costs were attributable to the ICU.[135]
A 2013 study found varying costs by facility for childbirth expenses in California, varying from $3,296 to $37,227 for vaginal birth and from $8,312 to $70,908 for a caesarean birth.[136]
Beginning in 2014, the United Kingdom National Institute for Health and Care Excellence began recommending that many women give birth at home under the care of a midwife rather than an obstetrician, citing lower expenses and better healthcare outcomes.[137] The median cost associated with home birth was estimated to be about $1,500 vs. about $2,500 in hospital.[138]
Childbirth routinely occurs in hospitals in many developed countries. Before the 20th century and in some countries to the present day, such as the Netherlands, it has more typically occurred at home.[139]
In rural and remote communities of many countries, hospitalized childbirth may not be readily available or the best option. Maternal evacuation is the predominant risk management method for assisting mothers in these communities.[140] Maternal evacuation is the process of relocating pregnant women in remote communities to deliver their babies in a nearby urban hospital setting.[140] This practice is common in Indigenous Inuit and Northern Manitoban communities in Canada as well as Australian aboriginal communities. There has been research considering negative effects of maternal evacuation due to a lack of social support provided to these women. These negative effects include an increase in maternal newborn complications and post-partum depression, and decreased breastfeeding rates.[140]
The exact location in which childbirth takes place is an important factor in determining nationality, in particular for birth aboard aircraft and ships.
Following are facilities that are particularly intended to house women during childbirth:
Different categories of birth attendants may provide support and care during pregnancy and childbirth, although there are important differences across categories based on professional training and skills, practice regulations, as well as the nature of care delivered. Many of these occupations are highly professionalised, but other roles exist on a less formal basis.
"Childbirth educators" are instructors who aim to educate pregnant women and their partners about the nature of pregnancy, labour signs and stages, techniques for giving birth, breastfeeding and newborn baby care. Training for this role can be found in hospital settings or through independent certifying organizations. Each organization teaches its own curriculum and each emphasizes different techniques.
Doulas are assistants who support mothers during pregnancy, labour, birth, and postpartum. They are not medical attendants; rather, they provide emotional support and non-medical pain relief for women during labour. Like childbirth educators and other unlicensed assistive personnel, certification to become a doula is not compulsory, thus, anyone can call themself a doula or a childbirth educator.
Confinement nannies are individuals who are employed to provide assistance and stay with the mothers at their home after childbirth. They are usually experienced mothers who took courses on how to take care of mothers and newborn babies.[141]
Midwives are autonomous practitioners who provide basic and emergency health care before, during and after pregnancy and childbirth, generally to women with low-risk pregnancies. Midwives are trained to assist during labour and birth, either through direct-entry or nurse-midwifery education programs. Jurisdictions where midwifery is a regulated profession will typically have a registering and disciplinary body for quality control, such as the American Midwifery Certification Board in the United States,[142] the College of Midwives of British Columbia (CMBC) in Canada[143][144] or the Nursing and Midwifery Council (NMC) in the United Kingdom.[145][146]
In the past, midwifery played a crucial role in childbirth throughout most indigenous societies. Although western civilizations attempted to assimilate their birthing technologies into certain indigenous societies, like Turtle Island, and get rid of the midwifery, the National Aboriginal Council of Midwives brought back the cultural ideas and midwifery that were once associated with indigenous birthing[132].
In jurisdictions where midwifery is not a regulated profession, traditional or lay midwives may assist women during childbirth, although they do not typically receive formal health care education and training.
Medical doctors who practice obstetrics include categorically specialized obstetricians, family practitioners and general practitioners whose training, skills and practices include obstetrics, and in some contexts general surgeons. These physicians and surgeons variously provide care across the whole spectrum of normal and abnormal births and pathological labour conditions. Categorically specialized obstetricians are qualified surgeons, so they can undertake surgical procedures relating to childbirth. Some family practitioners or general practitioners also perform obstetrical surgery. Obstetrical procedures include cesarean sections, episiotomies, and assisted delivery. Categorical specialists in obstetrics are commonly dually trained in obstetrics and gynecology (OB/GYN), and may provide other medical and surgical gynecological care, and may incorporate more general, well-woman, primary care elements in their practices. Maternal-fetal medicine specialists are obstetrician/gynecologists subspecialized in managing and treating high-risk pregnancy and delivery.
Anaesthetists or anesthesiologists are medical doctors who specialise in pain relief and the use of drugs to facilitate surgery and other painful procedures. They may contribute to the care of a woman in labour by performing epidurals or by providing anaesthesia (often spinal anaesthesia) for Cesarean section or forceps delivery.
Obstetric nurses assist midwives, doctors, women, and babies before, during, and after the birth process, in the hospital system. Obstetric nurses hold various certifications and typically undergo additional obstetric training in addition to standard nursing training.
Paramedics are healthcare providers that are able to provide emergency care to both the mother and infant during and after delivery using a wide range of medications and tools on an ambulance. They are capable of delivering babies but can do very little for infants that become "stuck" and are unable to be delivered vaginally.
Lactation consultants assist the mother and newborn to breastfeed successfully. A health visitor comes to see them at home, usually within 24 hours of discharge, and checks maternal healing and infant development.
Cultural values, assumptions, and practices of pregnancy and childbirth vary across cultures. For example, some Maya women who work in agricultural fields of some rural communities will usually continue to work in a similar function to how they normally would throughout pregnancy, in some cases working until labor begins.[147]
Comfort and proximity to extended family and social support systems may be a childbirth priority of many communities in developing countries, such as the Chillihuani in Peru and the Mayan town of San Pedro La Laguna.[147][148] Home births can help women in these cultures feel more comfortable as they are in their own home with their family around them helping out in different ways.[147] Traditionally, it has been rare in these cultures for the mother to lie down during childbirth, opting instead for standing, kneeling, or walking around prior to and during birthing.[148][147]
Some communities rely heavily on religion for their birthing practices. It is believed that if certain acts are carried out, then it will allow the child for a healthier and happier future. One example of this is the belief in the Chillihuani that if a knife or scissors are used for cutting the umbilical cord, it will cause for the child to go through clothes very quickly. In order to prevent this, a jagged ceramic tile is used to cut the umbilical cord.[148] In Mayan societies, ceremonial gifts are presented to the mother throughout pregnancy and childbirth in order to help her into the beginning of her child’s life.[147]
It is currently possible to collect two types of stem cells during childbirth: amniotic stem cells and umbilical cord blood stem cells.[149] They are being studied as possible treatments of a number of conditions.[149]
In many countries, age is reckoned from the date of birth, and sometimes the birthday is celebrated annually. East Asian age reckoning starts newborns at "1", incrementing each Lunar New Year.
Some cultures view the placenta as a special part of birth, since it has been the child's life support for so many months. The placenta may be eaten by the newborn's family, ceremonially, for nutrition, or otherwise.[150] (Some animal mothers eat their afterbirth; this is called placentophagy.) Most recently there is a category of birth professionals available who will process the placenta for consumption by postpartum mothers.
Natural birth topics:
The first stage begins with the onset of labor and ends when the cervix is fully opened. It is the longest stage of labor, usually lasting about 12 to 19 hours
..
The second stage involves pushing and delivery of your baby. It usually lasts 20 minutes to two hours.
Where nothing effective is done to avert maternal death, "natural" mortality is probably of the order of magnitude of 1,500/100,000.
17-pound baby born in Russia at Wikinews
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| リンク元 | 「分娩第1期」 |
| 関連記事 | 「labored」「stage」「first stage」「labor」「labo」 |