Prenatal Development, Birth, and the Newborn Baby

Essay assignment: Prenatal Development, Birth, and the Newborn Baby

An expectant mother reacts with amazement on hearing the robust heartbeat of her nearly full-term fetus. High-quality prenatal care and preparation for the events of childbirth enable her to approach labor and delivery with confidence and excitement.

chapter outline

·   Prenatal Development

·   Conception

·   Period of the Zygote

·   Period of the Embryo

·   Period of the Fetus

·   Prenatal Environmental Influences

·   Teratogens

·   Other Maternal Factors

·   The Importance of Prenatal Health Care

· ■  SOCIAL ISSUES: HEALTH  The Nurse–Family Partnership: Reducing Maternal Stress and Enhancing Child Development Through Social Support

·   Childbirth

·   The Stages of Childbirth

·   The Baby’s Adaptation to Labor and Delivery

·   The Newborn Baby’s Appearance

·   Assessing the Newborn’s Physical Condition: The Apgar Scale

·   Approaches to Childbirth

·   Natural, or Prepared, Childbirth

·   Home Delivery

·   Medical Interventions

·   Fetal Monitoring

·   Labor and Delivery Medication

·   Cesarean Delivery

·   Preterm and Low-Birth-Weight Infants

·   Preterm versus Small-for-Date Infants

·   Consequences for Caregiving

·   Interventions for Preterm Infants

Order an essay on Essay assignment: Prenatal Development, Birth, and the Newborn Baby

· ■  SOCIAL ISSUES: HEALTH  A Cross-National Perspective on Health Care and Other Policies for Parents and Newborn Babies

·   Birth Complications, Parenting, and Resilience

·   The Newborn Baby’s Capacities

·   Reflexes

·   States

·   Sensory Capacities

·   Neonatal Behavioral Assessment

· ■  BIOLOGY AND ENVIRONMENT  The Mysterious Tragedy of Sudden Infant Death Syndrome

·   Adjusting to the New Family Unit

When I met Yolanda and Jay one fall in my child development class, Yolanda was just two months pregnant. Approaching age 30, married for several years, and their careers well under way, they had decided to have a baby. To prepare for parenthood, they enrolled in my evening section, arriving once a week after work full of questions: “How does the baby grow before birth?” “When is each organ formed?” “Has its heart begun to beat?” “Can it hear, feel, or sense our presence?”

Most of all, Yolanda and Jay wanted to do everything possible to make sure their baby would be born healthy. Yolanda started to wonder about her diet and whether she should keep up her daily aerobic workout. And she asked me whether an aspirin for a headache, a glass of wine at dinner, or a few cups of coffee during work and study hours might be harmful.

In this chapter, we answer Yolanda and Jay’s questions, along with a great many more that scientists have asked about the events before birth. First, we trace prenatal development, paying special attention to environmental supports for healthy growth, as well as damaging influences that threaten the child’s health and survival. Next, we turn to the events of childbirth. Today, women in industrialized nations have many choices about where and how they give birth, and hospitals go to great lengths to make the arrival of a new baby a rewarding, family-centered event.

Yolanda and Jay’s son Joshua reaped the benefits of his parents’ careful attention to his needs during pregnancy. He was strong, alert, and healthy at birth. Nevertheless, the birth process does not always go smoothly. We will consider the pros and cons of medical interventions, such as pain-relieving drugs and surgical deliveries, designed to ease a difficult birth and protect the health of mother and baby. Our discussion also addresses the development of infants born underweight or too early. We conclude with a close look at the remarkable capacities of newborns.

Prenatal Development

The sperm and ovum that unite to form the new individual are uniquely suited for the task of reproduction. The ovum is a tiny sphere, measuring 1175 inch in diameter—barely visible to the naked eye as a dot the size of the period at the end of this sentence. But in its microscopic world, it is a giant—the largest cell in the human body. The ovum’s size makes it a perfect target for the much smaller sperm, which measure only 1500 inch.

Essay assignment: Prenatal Development, Birth, and the Newborn Baby

Conception

About once every 28 days, in the middle of a woman’s menstrual cycle, an ovum bursts from one of her ovaries, two walnut-sized organs located deep inside her abdomen, and is drawn into one of two fallopian tubes—long, thin structures that lead to the hollow, soft-lined uterus (see  Figure 3.1 ). While the ovum is traveling, the spot on the ovary from which it was released, now called the corpus luteum, secretes hormones that prepare the lining of the uterus to receive a fertilized ovum. If pregnancy does not occur, the corpus luteum shrinks, and the lining of the uterus is discarded two weeks later with menstruation.

The male produces sperm in vast numbers—an average of 300 million a day—in the testes, two glands located in the scrotum, sacs that lie just behind the penis. In the final process of maturation, each sperm develops a tail that permits it to swim long distances, upstream in the female reproductive tract, through the cervix (opening of the uterus) and into the fallopian tube, where fertilization usually takes place. The journey is difficult, and many sperm die. Only 300 to 500 reach the ovum, if one happens to be present. Sperm live for up to 6 days and can lie in wait for the ovum, which survives for only 1 day after being released into the fallopian tube. However, most conceptions result from intercourse occurring during a three-day period—on the day of ovulation or during the 2 days preceding it (Wilcox, Weinberg, & Baird,  1995 ).

With conception, the story of prenatal development begins to unfold. The vast changes that take place during the 38 weeks of pregnancy are usually divided into three phases: (1) the period of the zygote, (2) the period of the embryo, and (3) the period of the fetus. As we look at what happens in each, you may find it useful to refer to  Table 3.1 , which summarizes milestones of prenatal development.

Period of the Zygote

FIGURE 3.1 Female reproductive organs, showing fertilization, early cell duplication, and implantation.

(From Before We Are Born, 6th ed., by K. L. Moore & T. V. N. Persaud, p. 87. Copyright © 2003, reprinted with permission from Elsevier, Inc.)

The period of the zygote lasts about two weeks, from fertilization until the tiny mass of cells drifts down and out of the fallopian tube and attaches itself to the wall of the uterus. The zygote’s first cell duplication is long and drawn out; it is not complete until about 30 hours after conception. Gradually, new cells are added at a faster rate. By the fourth day, 60 to 70 cells exist that form a hollow, fluid-filled ball called a blastocyst (refer again to  Figure 3.1 ). The cells on the inside, called the embryonic disk, will become the new organism; the outer ring of cells, termed the trophoblast, will become the structures that provide protective covering and nourishment.