Introduction
Birth represents the culmination of an involved journey from a single-celled fertilized egg to a newborn baby. Normal, uncomplicated childbirth does not have any significant physical impact on the development of the baby. Neurological or physical abnormalities following a smooth delivery are most likely attributable to disruptions during prenatal development. Prenatal disruptions may be chromosomal, environmental, or some combination of the two and are studied in the field of teratology. Although the second and third trimesters of pregnancy are important, the first trimester of prenatal development is often considered most sensitive to disruptions. Disturbances during prenatal development can produce fetal death or severe abnormalities, such as deformed or missing limbs, cerebral palsy, or intellectual disabilities, as well as more subtle complications such as mood disorders or learning disabilities that may not manifest until later stages of development.
Most pregnancies in industrialized countries progress smoothly. When a mother experiences birth complications, however, the baby is at increased risk for adverse physical and neurological outcomes. Some of the more serious birth complications include anoxia, premature delivery, low birth weight, and contact with maternal genital herpes lesions at birth. In developing countries, babies may be at greater risk for physical or neurological damage due to a lack of medical facilities or trained medical personnel. As a result, birth complications can lead to fetal, and sometimes maternal, death; physical abnormalities such as paralysis or cerebral palsy; or neurological abnormalities such as intellectual disability or schizophrenia.
Stages of Labor
“Labor” is the term used to describe the process of the birth of the baby. Labor has three stages and begins when the cervix dilates. The cervix is the opening in the women’s vagina through which the baby passes. A common misconception is that labor begins with the onset of uterine contractions, but these are often present several hours before dilation. The duration of labor depends on a number of factors, the most important being the mother’s previous birth experience. On average, first-time mothers experience longer labors (eight to fourteen hours) than mothers who have given birth previously (three to eight hours).
The first stage of labor is the longest and most uncomfortable for the mother. It officially begins when the uterine contractions occur within fifteen-minute intervals and ends when the cervix is fully dilated so that the fetus can pass through. The second stage of labor represents the actual delivery of the baby. In vaginal childbirth (as opposed to cesarean section), the baby is pushed out through the expanding cervix, and average delivery time ranges from thirty to forty minutes. The third stage of labor takes about ten minutes and involves expulsion of the afterbirth, which comprises the placenta and other membranes. A physician will typically examine the afterbirth to ensure that all of it has been expelled. If not, the physician may scrape the uterus to remove the remaining portions and prevent infection.
The birth process is thought to be stressful on the baby but also adaptive. The contractions of the uterus during labor help push the baby out but may also restrict the oxygen supply to the fetus. This decrease of oxygen, called anoxia, can cause brain damage or fetal death if it persists beyond four minutes. In response to contractions during labor and the subsequent oxygen restriction, the fetus secretes hormones that increase blood flow to the brain and ensure that the baby will breathe on its own when it finally enters the extrauterine environment.
Childbirth Positions and Settings
There are considerable cultural variations in the childbirth process. For some cultures, childbirth is a communal occasion, while for others, it takes place in isolation. In most non-Western societies, childbirth takes place in a vertical position, such as squatting or sitting; in Western societies the mother is often placed on her back or side.
In the United States before the 1800s, the birth of a child took place at home, where the expectant mother was surrounded by family, relatives, and friends. In contrast, a modern setting is most likely to be a hospital. A majority of the births in the United States (98.8 percent in 2010) occur in a hospital setting. This percentage is lower in some European countries, where home births attended by midwives are more common.
Childbirth in a hospital setting is thought to have both advantages and disadvantages. The hospital setting is perceived to be less comfortable, less likely to allow extensive mother-baby contact at birth, and more likely to perform unnecessary medical interventions for issues that could be resolved without the risk of surgery. However, this setting is the most appropriate for older mothers and mothers who are likely to experience birth complications. Freestanding birth centers are thought to be more flexible, less likely to use unnecessary medical procedures, and more likely to encourage early contact between parents and the baby. Some developmental psychologists argue that the first twelve hours following birth are a critical period in the bonding experience between mother and baby. Without such initial contact, some developmental psychologists argue that the baby’s development will be suboptimal. The research in this area is inconclusive.
Home births are more frequent in Europe and developing countries than in North America. Advantages include a familiar environment and a setting that is in a position to promote parent-infant contact. Advocates of this setting indicate that the benefits of early attachment to the caregiver and the comfort level of the mother during the birth process outweigh any possible risks of being away from a hospital setting in the event of an emergency. If complications occur, however, the mother and baby must be transported to the hospital, jeopardizing the physical health of the baby by delaying what could be critical intervention.
In 2010, a midwife attended approximately 8 percent of US births in any of the described settings. A midwife is an individual experienced in the process of childbirth who assists with the delivery of the baby and provides emotional as well as educational support to the expectant mother. Midwives are common in many countries around the world, assisting pregnant women not only through birth but also through all stages of pregnancy.
Methods of Delivery
There are three types of delivery: natural, medicated, and cesarean. Natural childbirth avoids medication and requires education of the expectant mother to reduce fear and anxiety during childbirth, which are thought to increase the duration of labor and, as a result, the possibility of fetal complications. Prepared childbirth (the Lamaze method) was developed by French obstetrician Ferdinand Lamaze and is a type of natural childbirth. It includes not only education about childbirth but also training in special breathing techniques to control pushing in the final stages of labor. Other natural childbirth techniques, such as the Bradley method, have been developed, but these are usually variations of the Lamaze method.
Medicated childbirth uses a nonsurgical approach to expedite the delivery of the baby and to decrease the mother’s pain. Expectant mothers are commonly given oxytocics, synthetic hormones that expedite the birth process by stimulating uterine contractions. The American Academy of Pediatrics recommends the least possible use of medication such as tranquilizers or pain medications due to potential adverse impact on the newborn baby. Although it is difficult to predict the precise effects of medication on the fetus, it is customary to use minimal medicinal therapy. A general anesthetic such as Demerol is sometimes given to relieve the mother’s muscle tension and anxiety. This medication passes through the placenta and can lead to detrimental changes in the fetus, such as decreases in heart rate, muscle tone, breathing, and general attentiveness. One commonly used alternative is an epidural block, which has fewer side effects on the fetus than intravenous or oral medications. An epidural block entails the insertion of a needle into the spinal canal of the mother and the introduction of local anesthesia to numb the woman’s body from the waist down. A cesarean section commonly involves epidural analgesia so that the expectant mother can remain alert to greet her newborn baby.
A cesarean delivery is a surgical birth. The physician makes an incision in the mother’s abdomen and surgically removes the baby from her uterus. The indications for a cesarean section include previous cesarean births, abnormal labor, the presentation of the baby in breech position (buttocks first), and infant distress due to oxygen deprivation. In addition, a cesarean section might be necessary if there is serious maternal illness such as diabetes, premature separation of the placenta from the uterus (placenta abruptio), or maternal infection with genital herpes. Cesarean births require extra recovery time for the mother. Babies tend to be less alert and have greater breathing difficulties following cesarean delivery. However, there does not appear to be any significant lasting deleterious impact with cesarean delivery.
Baby’s Physical Appearance
At the time of birth, the baby is covered with protective grease called the vernix caeosa. This covering serves to protect the baby’s skin during birth. At birth the baby appears bluish in color (from oxygen deprivation) and may have a misshapen head, a flattened nose, and bruises. These characteristics are related to passage through the birth canal. The head is large compared to the rest of the body, and it has spaces between the skull bones (fontanelles) that allow it to contort slightly to fit through the birth canal. The fontanelles will close shortly after birth.
There are times during natural childbirth when a physician uses forceps or a vacuum extractor to deliver the baby. Forceps are a tonglike device used to pull the baby out of the mother’s birth canal. A vacuum extractor is a suction device that attaches to the baby’s head and pulls the baby out through the birth canal. Both forceps and vacuum extraction can contribute to transient bruises and misshapen features at birth.
Assessment of the Baby
There are two widely used methods of assessing the baby’s physical and neurological status following birth. The Apgar test
assesses the baby’s vital functions within sixty seconds of birth and again five minutes after birth by looking at heart rate, respiratory effort, reflex irritability, muscle tone, and color. A low score suggests possible physical or neurological abnormalities. A more thorough assessment may be conducted using the Brazelton Neonatal Behavior Assessment Scale (NBAS), which is administered a few days after birth. Areas assessed by the NBAS include reflex and respiratory responses and the infant’s capacity to respond to stimuli in an interactive process. For the NBAS, the baby is manipulated from sleep to wakefulness to crying and then back down to a quiet state. The baby’s coping and adaptive strategies are thus examined, and the baby’s physical and central nervous system functioning can be assessed.
Birth Complications
Although most births progress smoothly, some involve complications that can have a profound impact on the physical and neurological development of the baby. Premature birth is a significant risk factor for physical and neurological abnormalities. A baby’s physical status may be classified along two dimensions: birth weight and the length of time spent in the mother’s womb. A normal birth usually occurs between thirty-seven and forty-two weeks of pregnancy, and the baby averages 7.5 pounds. A fetus that is born prior to the twentieth week of pregnancy or weighs less than 1 pound will die. This type of birth is called a miscarriage. A fetus delivered between the twentieth and twenty-eighth week of pregnancy and weighing between 1 and 2 pounds is called immature. With the advancement of medical practices, it is possible for babies that are born as early as four months prematurely and weighing only 1.5 pounds to survive. A baby born between the twenty-ninth and thirty-sixth week of pregnancy and weighing between 2 and 5.5 pounds is termed premature. Both immature and premature births predispose a baby to a variety of adverse outcomes, ranging from death to severe physical and mental disabilities.
Low birth weight is another complication that predisposes a baby to adverse physical and neurological outcomes. Complications of low-birth-weight babies include greater incidences of intellectual disability, cerebral palsy, and general intellectual and gross motor delay. Babies weighing less than two pounds at birth are at risk for the most severe outcomes should they survive beyond infancy. Research indicates that nearly a quarter of these children experience intellectual disabilities, vision problems, and hearing difficulties. Babies weighing less than three pounds at birth continue to have a smaller physical stature and a significantly higher incidence of various illnesses throughout childhood. There is a clear relationship between premature birth, low birth weight, and adverse physical and neurological outcomes. A baby delivered prematurely is commonly a low-birth-weight baby. Both of these complications increase the baby’s risk for fetal death, physical abnormalities such as paralysis or cerebral palsy, and neurological abnormalities such as intellectual disability or schizophrenia.
Anoxia is another birth complication that is cause for particular concern. A cesarean section is performed when the fetus is at risk for prolonged oxygen deprivation. Newly born babies can tolerate oxygen deprivation for as long as four minutes, after which it can cause severe brain damage. There are several causes of anoxia. In many cases, the condition may occur as a result of constriction of the umbilical cord. This is common in a breech birth, in which the baby’s buttocks present for delivery rather than the baby’s head. A second cause of anoxia is premature separation of the placenta from the uterus, which interrupts the supply of oxygen to the fetus. Sedation given to the mother during childbirth is another risk factor for anoxia. Sedation crosses the placenta and interferes with the baby’s impetus to breathe. Anoxia may also occur as a result of airway obstruction from mucus inhaled during the birth process. This problem is typically alleviated through suctioning of the newborn’s airway at birth.
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