Childbirth (also called labour, birth, partus or parturition) is the culmination of a human pregnancy or gestation period with the delivery of one or more newborn infants from a woman's uterus. The process of human childbirth is categorized in three stages of labour: the shortening and dilation of the cervix, descent and delivery of the infant, and delivery of the placenta.
Because humans are bipedal with an erect stance and humans have relatively the biggest head and shoulders to the size of the pelvis of any species, humans fetuses 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 relatively large head and shoulders require a specific sequence of manoeuvres to occur for the bony head and shoulders to pass through the bony ring of the pelvis. If these manoeuvres fail, the progress of labour is arrested. All changes in the soft tissues of the cervix and the birth canal are entirely dependent on the successful completion of these six maneuvers:
Uterine muscles form opposing spirals from the top of the upper segment of the uterus to its junction with the lower segment. During effacement, the cervix becomes incorporated into the lower segment of the uterus. During a contraction, these muscles contract causing shortening of the upper segment and drawing upwards of the lower segment, in a gradual expulsive motion. This draws the cervix up over the baby's head. Full dilatation is reached when the cervix is the size of the baby's head; at around 10 cm dilation for a term baby.
The duration of labour varies widely, but active phase averages some 8 hours for women giving birth to their first child ("primiparae") and 4 hours for women who have already given birth ("multiparae").
Delivery of the fetal head signals the successful completion of the fourth mechanism of labour (delivery by extension), and is followed by the fifth and sixth mechanisms (restitution and external rotation).
The second stage of labour will vary to some extent, depending on how successfully the preceding tasks have been accomplished.
The third stage can be managed either expectantly or actively. Expectant management (also known as physiological management) allows the placenta to be expelled without medical assistance. Breastfeeding soon after birth and massaging of the top of the uterus (the fundus) causes uterine contractions that encourage delivery of the placenta. Active management utilizes oxytocic agents and controlled cord traction. The oxytocic agents augment uterine muscular contraction and the cord traction assists with rapid delivery of the placenta.
A Cochrane database study suggests that blood loss and the risk of postpartum bleeding will be reduced in women offered active management of the third stage of labour. However, the use of ergometrine for active management was associated with nausea or vomiting and hypertension, and controlled cord traction requires the immediate clamping of the umbilical cord.
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 China it is 30 days and is referred to as "doing the month" or "sitting month" (see Postpartum period). In some other 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.
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.
The human body also has a chemical response to pain, by releasing endorphins. Endorphins are present before, during, and immediately after childbirth. Some homebirth advocates believe that this hormone can induce feelings of pleasure and euphoria during childbirth, reducing the risk of maternal depression some weeks later.
Water birth is an option chosen by some women for pain relief during labor and childbirth, and some studies have shown waterbirth in an uncomplicated pregnancy to reduce the need for analgesia, without evidence of increased risk to mother or newborn. Hot water tubs are available in many hospitals and birthing centres.
Meditation and mind medicine techniques for the use of pain control during labour and delivery. These techniques are used in conjunction with progressive muscle relaxation and many other forms of relaxation for the mind and body to aid in pain control for women during childbirth. One such technique is the use of hypnosis in childbirth.
Popular medical pain control in hospitals include the regional anesthetics epidural blocks, and spinal anaesthesia. Epidural analgesia is a 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. One study found that the women receiving epidural analgesia had more fear before the administering of the epidural than those who did not receive it, but that they did not necessarily have more pain. Medicine administered via epidural can cross the placenta and enter the bloodstream of the fetus. 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.
Secondary changes may be observed: swelling of the tissues, maternal exhaustion, fetal heart rate abnormalities. Left untreated, severe complications include death of mother or baby, and genitovaginal fistula. These are commonly seen in Third World countries where births are often unattended or attended by poorly trained community members.
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 know as diastasis of the pubic symphysis. Predisposing factors for girdle pain include maternal obesity.
Infection remains a major cause of mortality and morbidity in the developing world today. 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 (MMR) rate varies from 9/100,000 live births in the US and Europe, to 900/100,000 live births in Sub-Saharan Africa.
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.
Neonates 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:
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 "natural" mortality rate of childbirth—where nothing is done to avert maternal death—has been estimated as being between 1,000 and 1,500 deaths per 100,000 births. (See main article: neonatal death, maternal death)
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). "Medical care" in this context does not refer specifically to treatment in hospitals, but simply routine prenatal care and the presence, at the birth, of an attendant with birthing skills.
A 1983-1989 study by the Texas Department of Health 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. 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: The term Fetal distress is emotive and misleading. True intrapartum asphyxia is the impairment 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. 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.
Twins can be delivered vaginally. In some cases twin delivery is done in a larger delivery room or in theatre, just in case complications occur e.g.
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.
Maternal-fetal medicine specialists are experts in managing and treating high-risk pregnancy and delivery. They are usually also obstetricians.
Midwives provide care to low-risk pregnant mothers. Midwives may be licensed and registered, or may be lay practitioners. Jurisdictions with legislated midwives will typically have a registering and disciplinary body, such as a College of Midwifery. Registered midwives are trained to assist a mother with labour and birth, either through direct-entry or nurse-midwifery programs. Lay midwives, who are usually not licensed or registered, typically gain experience through apprenticeship with other lay midwives.
Obstetricians provide care for normal and abnormal births and pathological labour conditions. Obstetricians are trained surgeons, so they can undertake surgical procedures relating to childbirth. Such procedures include cesarean sections, episiotomies, or assisted delivery. Most obstetricians also provide gynecological care, and may have a primary, well-woman, care element to their practices.
Obstetric nurses assist midwives, doctors, women, and babies prior to, during, and after the birth process, in the hospital system. Some midwives are also obstetric nurses. Obstetric nurses hold various certifications and typically undergo additional obstetric training in addition to standard nursing training.
Some families view the placenta as a special part of birth, since it has been the child's life support for so many months. Some parents like to see and touch this organ. In some cultures, parents plant a tree along with the placenta on the child's first birthday. The placenta may be eaten by the newborn's family, ceremonially or otherwise.
While many women experience joy, relief, and elation upon the birth of their child, some women report symptoms compatible with post-traumatic stress disorder (PTSD) after birth. Between 70 and 80% of mothers in the United States report some feelings of sadness or "baby blues" after childbirth. Postpartum depression may develop in some women; about 10% of mothers in the United States are diagnosed with this condition. Abnormal and persistent fear of childbirth is known as tokophobia.
Preventative group therapy has proven effective as a prophylactic treatment for postpartum depression.
It is the traditional history of home labour that makes The Netherlands an attractive site for studies related to birth. One third of all baby deliveries there are still happening at home in contrast with other western industrialized countries. Apparently, Dutch fathers have been in the scene of labour for a long time as can be observed in paintings from the 17th and 18th centuries.
During this study , it was found that fathers can have different roles during birth and that little is said about the conflicts between partners or partners and professionals. Among other findings were also: the interpretation of the presence of fathers during birth as a modern version of the anthropological couvade ritual to ease the woman's pain; the majority of fathers did not perceive any limitation to participate in their childbirth and upper generations did not play an important rule in the transmission of knowledge about birth to those fathers but the wives, feminine acquaintances and midwives.
The research was based, mainly, on in-depth interviews, where fathers described what was happening from their partner’s first signals of birth labour until the placenta delivery.