Chapter Three

At no other time in the lifespan is change as rapid as it is before birth. Prenatal development takes place in three phases: (1) the period of the zygote, (2) the period of the embryo, and (3) the period of the fetus. Various environmental agents and maternal conditions can damage the developing organism, making the prenatal period a vulnerable time. For this reason, prenatal health care is vitally important to ensure the health of mother and baby.

Childbirth takes place in three stages: (1) dilation and effacement of the cervix, (2) delivery of the baby, and (3) birth of the placenta. Production of stress hormones helps the infant withstand the trauma of childbirth, and the baby’s physical condition is assessed immediately after birth using the Apgar Scale. Alternatives to traditional hospital childbirth include natural childbirth and delivery in a birth center or at home. Still, childbirth in the United States is often accompanied by a variety of medical interventions. Although they help save the lives of many babies, these procedures can cause problems of their own when used routinely. When birth complications occur, they most often involve preterm and low-birth-weight infants. Fortunately, many of these babies recover from difficulties with the help of supportive home environments.

Infants begin life with a remarkable set of skills for relating to the surrounding world. They display a wide variety of reflexes, and, with the exception of vision, their senses are well developed. In the early weeks, babies move in and out of different states of arousal frequently. They first communicate by crying, and with experience, parents become better at interpreting and responding to infants’ cries. Tests of newborn behavior allow the assessment of the baby’s many capacities. The baby’s arrival is exciting, but it brings with it profound changes. Husbands and wives who support each other’s needs typically adjust well to the demands of parenthood.