Childbirth

Childbirth, labour, delivery, birth, partus, or parturition is the culmination of a period of pregnancy with the expulsion of one or more newborn infants from a woman's uterus. The process of normal childbirth is categorized in three stages of labour: the shortening and dilation of the cervix, descent and birth of the infant, and birth of the placenta.[1]

Signs and symptoms Pain 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,[2][3] mobility during labour and the support given during labour. One small study found that Middle Eastern women, especially those with a low educational background, had more painful experiences during childbirth.[4]

Pain is only one factor of many influencing women's experience with the process of childbirth. A systematic review of 137 studies found that personal expectations, the amount of support from caregivers, quality of the caregiver-patient relationship, and involvement in decisionmaking 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.[5]

Descriptions 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.[6]

Psychological 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.

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.[7] Oxytocin is further released during labor 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.[8]

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.[9] 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.[10][11]

Normal birth 
Sequence of images showing the stages of ordinary childbirth.Further information: Vaginal delivery
Because humans are bipedal with an erect stance and have, in relation to the size of the pelvis, the biggest head of any mammalian species, human fetuses and human female pelvises are adapted to make birth possible.

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 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 (head-first presentation) delivery:

1.Engagement of the fetal head in the transverse position. The baby's head is facing across the pelvis at one or other of the mother's hips.
2.Descent and flexion of the fetal head.
3.Internal rotation. The fetal head rotates 90 degrees to the occipito-anterior position so that the baby's face is towards the mother's rectum.
4.Delivery by extension. The fetal head passes out of the birth canal. Its head is tilted forwards so that the crown of its head leads the way through the vagina.
5.Restitution. The fetal head turns through 45 degrees to restore its normal relationship with the shoulders, which are still at an angle.
6.External rotation. The shoulders repeat the corkscrew movements of the head, which can be seen in the final movements of the fetal head.
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.[12]

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.[13]

Onset of labor There are various definitions of the onset of labor, including:

Regular uterine contractions at least every six minutes with evidence of change in cervical dilation or cervical effacement between consecutive digital examinations.[14]
Regular contractions occurring less than 10 min apart and progressive cervical dilation or cervical effacement.[15]
At least 3 painful regular uterine contractions during a 10-minute period, each lasting more than 45 seconds.[16]
In order to avail for more uniform terminology, the first stage of labor is divided into "latent" and "active" phases, where the latent phase is sometimes included in the definition of labor,[17] and sometimes not.[18]

First stage: latent phase The latent phase of labour is also called prodromal labour or pre-labour. It is a subclassification of the first stage".[19]

The latent phase is generally defined as beginning at the point at which the woman perceives regular uterine contractions.[20] In contrast, Braxton Hicks contractions, which are contractions that may start around 26 weeks gestation and are sometimes called "false labour", should be infrequent, irregular, and involve only mild cramping.[21]

Cervical effacement, which is the thinning and stretching of the cervix, and cervical dilation occur during the closing weeks of pregnancy and is usually complete or near complete, by the end of the latent phase.[22] The degree of cervical effacement may be felt during a vaginal examination. A 'long' cervix implies that effacement has not yet occurred. Latent phase ends with the onset of active first stage, and this transition is defined retrospectively.

First stage: active phase The active stage of labour (or "active phase of first stage" if previous phase is termed "latent phase of first stage") confers an accelerated cervical dilation. In the US, the definition of active labor has changed from 3 to 4 centimeters to 5 cm for multiparous women and at 6 cm for nulliparous women.[23] This has been done in an effort to increase the rates of vaginal delivery.[24]

A definition of active labor in a British journal was having contractions more frequent than every 5 minutes, in addition to either a cervical dilation of 3 cm or more or a cervical effacement of 80% or more.[25]

In Sweden, the onset of the active phase of labor is defined as when two of the following criteria are met:[26]

three to four contractions every ten minutes
rupture of membranes
cervical dilation of 3 to 4 centimeters
Health care providers may assess a laboring mother's progress in labor 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 labor.

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.

The duration of labour varies widely, but active phase averages some 8 hours[27] for women giving birth to their first child ("primiparae") and shorter for women who have already given birth ("multiparae"). Active phase prolongation is defined as in a primigravid woman as the failure of the cervix to dilate at a rate of 1.2 cm/hr over a period of at least two hours. This definition is based on Friedman's Curve, which plots the typical rate of cervical dilation and fetal descent during active labour.[28] Some practitioners may diagnose "Failure to Progress", and consequently, propose interventions to optimize chances for healthy outcome.[29]

 
Sequence of cervix dilation during labour

Second stage: fetal expulsion 
Stages in the birth of the baby's head. (Illustration by Frank Netter)This 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.

Complete expulsion of the baby signals the successful completion of the second stage of labour.

The second stage of birth will vary by factors including parity (the number of children a woman has had), fetal size, anesthesia, and the presence of infection. Longer labours are associated with declining rates of spontaneous vaginal delivery and increasing rates of infection, perineal laceration, and obstetric hemorrhage, as well as the need for intensive care of the neonate.[30]

Third stage: delivery of the placenta Further information: Umbilical cord and Placental expulsion
 
A newborn baby with umbilical cord ready to be clamped
Breastfeeding during and after the third stage, the placenta is visible in the bowl to the right.The period from just after the fetus is expelled until just after the placenta is expelled is called the third stage of labour.

Delaying the clamping of the umbilical cord until at least one minute after birth improves outcomes as long as there is the ability to treat jaundice if it occurs.[31] In some birthing centers, this may be delayed by 5 minutes or more, or omitted entirely. Delayed clamping of the cord decreases the risk of anemia but may increase risk of jaundice. Clamping is followed by cutting of the cord, which is painless due to the absence of nerves.

Placental expulsion begins as a physiological separation from the wall of the uterus. The period from just after the fetus is expelled until just after the placenta is expelled is called the third stage of labour. 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[32] 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.[33]

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.[34] 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.[35][36][37]

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".

Fourth stage Further information: Postnatal
The "fourth stage of labour" is the period beginning immediately after the birth of a child and extending for about six weeks. Another term would be postpartum period, as it refers to the mother (whereas postnatal refers to the infant). Less frequently used is puerperium.[38]

Many cultures feature initiation rites for newborns, such as circumcision, naming ceremonies, baptism, and others.

Mothers are often allowed a period where they are relieved of their normal duties to recover from childbirth. The length of this period varies. In many countries, taking time off from work to care for a newborn is called "maternity leave" or "parental leave" and can vary from a few days to several months.

Management 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,[39] 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.[40] A 2013 Cochrane review pointed out that in recent years, obstetrical anaesthesia has changed considerably, with better general anaesthetic techniques and a greater use of regional anaesthesia and reported "no benefits or harms of restricting foods and fluids during labour in women at low risk of needing anaesthesia." The review suggested "fasting does not guarantee an empty stomach or less acidity" and that "poor nutritional balance may be associated with longer and more painful labours." The review concluded that "women should be free to eat and drink in labour, or not, as they wish."[41]

Active management Active management of labour consists of a number of care principles, including frequent assessment of cervical dilatation. If the cervix is not dilating, oxytocin is offered. This management results in a slightly reduced number of caesarean births, but does not change how many women have assisted vaginal births. 75% of women report that they are very satisfied with either active management or normal care.[42]

Perineal shaving At one time shaving of the perineum, 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. A 2009 Cochrane review found no evidence of any clinical benefit with perineal shaving. The review did find side effects including irritation, redness, and multiple superficial scratches from the razor.[43]

Labour induction and elective cesarean 
The child as it is passing out through the vagina must pass through the lesser pelvis.
The hormones initiating labor.In many cases and with increasing frequency, childbirth is achieved through induction of labor or caesarean section, which is the removal of the neonate through a surgical incision in the abdomen, rather than through vaginal birth.[44] Childbirth by C-Sections increased 50% in the U.S. from 1996 to 2006, and comprise nearly 32% of births in the U.S. and Canada.[44][45] Medical professional policy makers find that prior to 39 weeks induced births and elective cesarean can be harmful to the neonate as well as harmful or without benefit to the mother, and have endorsed guidelines for non-medically indicated induced births and elective cesarean before 39 weeks.[46]

The prevalence of labour induction in the United States is 22%, and has more than doubled tfrom 1990 to 2006.[45][47] The incidence of cesarean in the US and Canada is 32% and has increased 50% in the US from 1996 to 2006.[44][45]

Health conditions that may warrant induced labour or cesarean delivery include gestational or chronic hypertension, preeclampsia, eclampsia, diabetes, premature rupture of membranes, severe fetal growth restriction, and post-term pregnancy. Cesarean section too may be of benefit to both the mother and baby for certain indications including maternal HIV/AIDS, fetal abnormality, breech position, fetal distress, multiple gestations, and maternal medical conditions which would be worsened by labour or vaginal birth.

Pitocin is the most commonly used agent for induction in the United States, and is used to induce uterine contractions. Other methods of inducing labour include stripping of the amniotic membrane, artificial rupturing of the amniotic sac (called amniotomy), or nipple stimulation. Ripening of the cervix can be accomplished with the placement of a Foley catheter or the use of synthetic prostaglandins such as misoprostol.[45] A large review of methods of induction was published in 2011.[48]

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:

Abruptio placentae
Chorioamnionitis
Fetal compromise such as isoimmunization leading to hemolytic disease of the newborn or oligohydramnios
Fetal demise
Gestational hypertension
Maternal conditions such as gestational diabetes or chronic kidney disease
Preeclampsia or eclampsia
Premature rupture of membranes
Postterm pregnancy
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.[49]

Pain control Non pharmaceutical
Some women prefer to avoid analgesic medication during childbirth. They can try using psychological preparation, education, massage, or water therapy in a tub or shower. Some women like to have someone to support them during labour and birth, such as the father of the baby, a family member, a close friend, a partner, or a doula. The body also releases endorphins that reduce pain.[50]

Water immersion may help with pain in the first stage of labor but is not recommended in the second stage due to concerns regarding complication.[51] Water birth is thus not recommended.[52]

The injection of small amounts of sterile water into or just below the skin at several points on the back has been a method tried to reduce labor pain, but no good evidence shows that it actually helps.[53]

Pharmaceutical
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 50% nitrous oxide, 50% oxygen, known as Entonox; in the UK, midwives may use this gas without a doctor's prescription. Opioids such as fentanyl maybe used, but if given too close to birth there is a risk of respiratory depression in the infant.

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.[54] Generally, pain and cortisol increased throughout labour in women without EDA. Pain and stress hormones rise throughout labour for women without epidurals, while pain, fear, and stress hormones decrease upon administration of epidural analgesia, but may rise again later.[55] Medicine administered via epidural can cross the placenta and enter the bloodstream of the fetus.[56] 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.[57]

Augmentation Augmentation is the process of facilitating further labour. Oxytocin has been used to increase the rate of vaginal delivery in those with a slow progress of labour.[58]

 
Oxytocin facilitates labour and will follow a positive feedback loop.Episiotomy Further information: Episiotomy
Vaginal 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. The midwife or obstetrician may decide to make a surgical cut to the perineum (episiotomy) to make the baby's birth easier and prevent severe tears that can be difficult to repair. A 2012 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, however they found that women experienced more anterior perineal damage with restrictive episiotomy.[59]

Instrumental delivery Obstetric forceps or ventouse may be used to facilitate childbirth.

Multiple births In cases of a cephalic presenting twin (first baby head down), 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.

Both twins born vaginally—this can occur both presented head first or where one comes head first and the other is breech and/or helped by a forceps/ventouse delivery
One twin born vaginally and the other by caesarean section.
If the twins are joined at any part of the body—called conjoined twins, delivery is mostly by caesarean section.
Support See also: Men's role in childbirth
 
Baby on warming tray attended to by her father.Historically women have been attended and supported by other women during labor and birth. However currently, as more women are giving birth in a hospital rather than at home, continuous support has become the exception rather than the norm. When women became pregnant any time 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. “Her husband was attentive and kind, but, Kirby concluded, Every good woman needs a companion of her own sex."[60] Obstetric care frequently subjects women to institutional routines, which may have adverse effects on the progress of labor. Supportive care during labor may involve emotional support, comfort measures, and information and advocacy which may promote the physical process of labor 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.[61]

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."[62]

Monitoring Fetus External monitoring For monitoring of the fetus during childbirth, a simple pinard stethoscope or doppler fetal monitor ("doptone") can be used. A method of external foetal 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[63] Monitoring with a cardiotocograph can either be intermittent or continuous.

Invasive monitoring A mother's waters have to break before invasive monitoring can be used. More invasive monitoring can involve a foetal scalp electrode to give an additional measure of fetal heart activity, and/or intrauterine pressure catheter (IUPC). It can also involve foetal scalp pH testing.

Mother Sometimes a mother may need monitoring during childbirth, parameters such as pulse, blood pressure, reflexes and the percentage of oxygen in the blood (pulse oximetry) can be measured.[citation needed]

Collecting stem cells It is currently possible to collect two types of stem cells during childbirth: amniotic stem cells or umbilical cord blood stem cells.[citation needed] To collect amniotic stem cells, it is necessary to do amniocentesis before or during the birth.[citation needed] Amniotic fluid contains mesenchymal stem cells while umbilical cord blood contains both hematopoietic and mesenchymal stem cells.[citation needed] Although there are many potential future applications of such stem cells, there are few current therapeutic applications of such stem cells.[64][65][66]

Complications See also: Birth trauma (physical) and Childbirth-related posttraumatic stress disorder
 
Disability-adjusted life year for maternal conditions per 100,000 inhabitants in 2002.[67]
  no data
  less than 100
  100-400
  400-800
  800-1200
  1200-1600
  1600-2000
  2000-2400
  2400-2800
  2800-3200
  3200-3600
  3600-4000
  more than 4000
Disability-adjusted life year for perinatal conditions per 100,000 inhabitants in 2002.[67]
  no data
  less than 100
  100-400
  400-800
  800-1200
  1200-1600
  1600-2000
  2000-2400
  2400-2800
  2800-3200
  3200-3600
  3600-4000
  more than 4000Childbirth is an inherently dangerous and risky activity, subject to many complications. The "natural" mortality rate of childbirth—where nothing is done to avert maternal death—has been estimated at 1500 deaths per 100,000 births.[68] (See main articles: neonatal death, maternal death). Modern medicine has greatly alleviated the risk of childbirth. In modern Western countries, such as the United States and Sweden, the current maternal mortality rate is around 10 deaths per 100,000 births.[68]:p.10 As of June 2011, about one third of American births have some complications, "many of which are directly related to the mother's health."[69]

Birthing complications may be maternal or fetal, and long term or short term.

Pre-term Newborn mortality at 37 weeks may be 2.5 times the number at 40 weeks, and was elevated compared to 38 weeks of gestation. These “early term” births were also associated with increased death during infancy, compared to those occurring at 39 to 41 weeks ("full term").[46] Researchers found benefits to going full term and “no adverse effects” in the health of the mothers or babies.[46]

Medical researchers find that neonates born before 39 weeks experienced significantly more complications (2.5 times more in one study) compared with those delivered at 39 to 40 weeks. Health problems among babies delivered "pre-term" included respiratory distress, jaundice and low blood sugar.[46][70] The American Congress of Obstetricians and Gynecologists and medical policy makers review research studies and find increased incidence of suspected or proven sepsis, RDS, Hypoglycemia, need for respiratory support, need for NICU admission, and need for hospitalization > 4 – 5 days. In the case of cesarean sections, rates of respiratory death were 14 times higher in pre-labour at 37 compared with 40 weeks gestation, and 8.2 times higher for pre-labour cesarean at 38 weeks. In this review, no studies found decreased neonatal morbidity due to non-medically indicated (elective) delivery before 39 weeks.[46]

Labour complications The second stage of labour may be delayed or lengthy due to:

malpresentation (breech birth (i.e. buttocks or feet first), face, brow, or other)
failure of descent of the fetal head through the pelvic brim or the interspinous diameter
poor uterine contraction strength
active phase arrest
cephalo-pelvic disproportion (CPD)
shoulder dystocia
Secondary changes may be observed: swelling of the tissues, maternal exhaustion, fetal heart rate abnormalities. Left untreated, severe complications include death of mother and/or baby, and genitovaginal fistula.

Dystocia (obstructed labour) Main article: Obstructed labour
Obstructed labour, dystocia (antonym eutocia; Ancient Greek: τόκος tókos “childbirth”) is an abnormal or difficult childbirth or labour. Approximately one fifth of human labours have dystocia.[71] Dystocia may arise due to incoordinate uterine activity, abnormal fetal lie or presentation, absolute or relative cephalopelvic disproportion, or (rarely) a massive fetal tumor such as a sacrococcygeal teratoma. Oxytocin is commonly used to treat incoordinate uterine activity, but pregnancies complicated by dystocia often end with assisted deliveries, including forceps, ventouse or, commonly, caesarean section. Recognized complications of dystocia include fetal death, respiratory depression, hypoxic ischaemic encephalopathy (HIE), and brachial nerve damage. A prolonged interval between pregnancies, primigravid birth, and multiple birth have also been associated with increased risk for labor dystocia.[71]

Shoulder dystocia is a dystocia in which the anterior shoulder of the infant cannot pass below the pubic symphysis or requires significant manipulation to pass below it. It can also be described as delivery requiring additional manoeuvres after gentle downward traction on the head has failed to deliver the shoulders.

A prolonged second stage of labour is another type of dystocia whereby the fetus has not been delivered within three hours in a nulliparous woman, or two hours in multiparous woman, after her cervix has become fully dilated.

Synonyms for dystocia include difficult labour, abnormal labour, difficult childbirth, abnormal childbirth, and dysfunctional labour.

Maternal complications Vaginal birth injury with visible tears or episiotomies are common. Internal tissue tearing as well as nerve damage to the pelvic structures lead in a proportion of women to problems with prolapse, incontinence of stool or urine and sexual dysfunction. Fifteen percent of women become incontinent, to some degree, of stool or urine after normal delivery, this number rising considerably after these women reach menopause. Vaginal birth injury is a necessary, but not sufficient, cause of all non hysterectomy related prolapse in later life. Risk factors for significant vaginal birth injury include:

A baby weighing more than 9 pounds.
The use of forceps or vacuum for delivery. These markers are more likely to be signals for other abnormalities as forceps or vacuum are not used in normal deliveries.
The need to repair large tears after delivery.
Pelvic girdle pain. Hormones and enzymes work together to produce ligamentous relaxation and widening of the symphysis pubis during the last trimester of pregnancy. Most girdle pain occurs before birthing, and is known as diastasis of the pubic symphysis. Predisposing factors for girdle pain include maternal obesity.

Infection remains a major cause of maternal mortality and morbidity in the developing world. The work of Ignaz Semmelweis was seminal in the pathophysiology and treatment of puerperal fever and saved many lives.

Hemorrhage, or heavy blood loss, is still the leading cause of death of birthing mothers in the world today, especially in the developing world. Heavy blood loss leads to hypovolemic shock, insufficient perfusion of vital organs and death if not rapidly treated. Blood transfusion may be life saving. Rare sequelae include Hypopituitarism Sheehan's syndrome.

The maternal mortality rate (MMR) varies from 9 per 100,000 live births in the US and Europe to 900 per 100,000 live births in Sub-Saharan Africa.[72] Every year, more than half a million women die in pregnancy or childbirth.[73]

Fetal complications 
Mechanical fetal injury may be caused by improper rotation of the fetus.Mechanical fetal injury 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.[74]

Neonatal infection 
Disability-adjusted life year for neonatal infections and other (perinatal) conditions per 100,000 inhabitants in 2004. Excludes prematurity and low birth weight, birth asphyxia and birth trauma which have their own maps/data.[75]
  no data
  less than 150
  150-300
  300-450
  450-600
  600-750
  750-900
  900-1050
  1050-1200
  1200-1350
  1350-1500
  1500-1850
  more than 1850Neonates are prone to infection in the first month of life. Some organisms such as S. agalactiae (Group B Streptococcus) or (GBS) are more prone to cause these occasionally fatal infections. Risk factors for GBS infection include:

prematurity (birth before 37 weeks gestation)
a sibling who has had a GBS infection
prolonged labour or rupture of membranes
Untreated sexually transmitted infections are associated with congenital and perinatal infections in neonates, particularly in the areas where rates of infection remain high. The overall perinatal mortality rate associated with untreated syphilis, for example, is 30%.[76]

Neonatal death Infant deaths (neonatal deaths from birth to 28 days, or perinatal deaths if including fetal deaths at 28 weeks gestation and later) are around 1% in modernized countries.

The most important factors affecting mortality in childbirth are adequate nutrition and access to quality medical care ("access" is affected both by the cost of available care, and distance from health services).[citation needed]

A 1983-1989 study by the Texas Department of State Health Services highlighted the differences in neonatal mortality (NMR) between high risk and low risk pregnancies. NMR was 0.57% for doctor-attended high risk births, and 0.19% for low risk births attended by non-nurse midwives. Conversely, some studies demonstrate a higher perinatal mortality rate with assisted home births.[77] Around 80% of pregnancies are low-risk. Factors that may make a birth high risk include prematurity, high blood pressure, gestational diabetes and a previous cesarean section.

Intrapartum asphyxia Intrapartum asphyxia is the impairment of the delivery of oxygen to the brain and vital tissues during the progress of labour. This may exist in a pregnancy already impaired by maternal or fetal disease, or may rarely arise de novo in labour. This can be termed fetal distress, but this term may be emotive and misleading. True intrapartum asphyxia is not as common as previously believed, and is usually accompanied by multiple other symptoms during the immediate period after delivery. Monitoring might show up problems during birthing, but the interpretation and use of monitoring devices is complex and prone to misinterpretation. Intrapartum asphyxia can cause long-term impairment, particularly when this results in tissue damage through encephalopathy.[78]

Society and culture Further information: Ageing
 
Medieval woman giving birth. France, 12th centuryChildbirth routinely occurs in hospitals in much of Western society. Before the 20th century and in some countries to the present day it has more typically occurred at home.[79]

In Western and other cultures, 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 families 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 or otherwise (for nutrition; the great majority of animals in fact do this naturally).[80] Most recently there is a category of birth professionals available who will encapsulate placenta for use as placenta medicine by postpartum mothers.

The exact location in which childbirth takes place is an important factor in determining nationality, in particular for birth aboard aircraft and ships.

Facilities Following are facilities that are particularly intended to house women during childbirth:

A labour ward, also called a delivery ward or labour and delivery, is generally a department of a hospital that focuses on providinghealth care to women and their children during childbirth. It is generally closely linked to the hospital's neonatal intensive care unit and/or obstetric surgery unit if present. A maternity ward or maternity unit may include facilities both for childbirth and for postpartum rest and observation of mothers in normal as well as complicated cases.
A birthing center generally presents a simulated home-like environment. Birthing centers may be located on hospital grounds or "free standing" (i.e., not hospital-affiliated).
In addition, it is possible to have a home birth.

Associated professions 
Model of pelvis used in the beginning of the 19th century to teach technical procedures for a successful childbirth. Museum of the History of Medicine, Porto Alegre, BrazilDifferent 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 nature of care delivered.

“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. In the United States and elsewhere, classes for training as a childbirth educator can be found in hospital settings or through many independent certifying organizations such as Birthing From Within, BirthWorks, The Bradley Method, Birth Arts International, CAPPA, HypBirth, HypnoBabies, HypnoBirthing, ICTC, ICEA, Lamaze, etc. Each organization teaches its own curriculum and each emphasizes different techniques. Information about each can be obtained through their individual websites.

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 assistive personnel, certification to become a doula is not compulsory, thus, anyone can call themself a doula or a childbirth educator.

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,[81] the College of Midwives of British Columbia (CMBC) in Canada[82][83] or the Nursing and Midwifery Council (NMC) in the United Kingdom.[84][85]

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.