In the last 2 to 3 months of pregnancy, 6% to 7% of women experience toxemia (tock – SEE-mee-uh), or preeclampsia (pre-ee-CLAMP-see-uh). Symptoms include rapid weight gain, fluid retention, an increase in blood pressure, and protein in the urine. If toxemia is allowed to progress, it can result in eclampsia, which involves convulsions, coma, and, in approximately 15% of cases, death. Eclampsia is a leading cause of mater­nal and fetal death in the United States today (Lipstein et al., 2003). These conditions, which occur primarily in women who neglect good prenatal care, are relatively rare in women with good medical care. Overall, African American women are at higher risk for eclampsia (MacKay et al., 2001).

One study found that the longer a woman has a monogamous relationship before she conceives, the less likely she is to develop preeclampsia and eclampsia (D. A. Clark, 1994). It has been suggested that longer relationships will produce a female immune re­sponse to certain chemicals in the sperm that may lead to complications with preeclampsia. Women whose mother experienced preeclampsia are more likely to expe­rience preeclampsia in their own pregnancies, and male offspring from mothers with preeclampsia are twice as likely to father children through a preeclampsia pregnancy as are men who were born from a normal pregnancy (Seppa, 2001).

The average length of a pregnancy is 9 months, but a normal birth can occur 3 weeks before or 2 weeks after the due date. It is estimated that only 4% of American babies are born exactly on the due date predicted (Dunham et al., 1992). Early delivery may occur in cases in which the mother has exercised throughout the pregnancy, the fetus is fe­male, or the mother has shorter menstrual cycles (R. Jones, 1984).

No one really knows why, but there is also a seasonal variation in human birth. More babies are born between July and October (meaning that more conceptions occur dur­ing the late fall and early winter). It has been hypothesized that this evolved because of the increased food supply available during the late summer and early fall months (al­though perhaps more couples engage in sexual intercourse to keep warm in the cold win­ter months!). There are also more babies born between the hours of 1 and 7 A. M., and again this is thought to have evolved because of the increased protection and decreased chances of predator attacks (R. Jones, 1984).

We do not know exactly what starts the birth process. It appears that in fetal sheep there is a chemical in the brain that signals it is time for birth (Palca, 1991). Perhaps this may also be true in humans, but the research is still incomplete.

Question: What determines how long a woman will be in labor? Why do they say a woman’s first baby is hardest? A friend of mine was in labor for 36 hours!

Подпись:Подпись:Usually, first labors are the most difficult. Second and subsequent labors are usually easier and shorter because there is less resistance from the birth canal and the surrounding muscles. Overall, the biggest differences are in the amount of time it takes for the cervix to fully dilate and the amount of pushing necessary to move the baby out of the birth canal. The first labor usu­ally takes anywhere between 8 and 14 hours, whereas second and subsequent labors usually take anywhere between 4 and 9 hours. However, labor can, and often does, last up to 24 hours. We do not really know why some women have easier labors than others. Perhaps it could be due to diet and/or exercise during the pregnancy.

Подпись: Lamaze A prepared childbirth method in which couples are provided information about the birth process and are taught breathing and relaxation exercises to use during labor. Подпись:Подпись:As the birth day comes closer, many women (and men too!) become anxious, nervous, and excited about what is to come. This is probably why the tradition of baby showers started. These gatherings enable women (and more recently, men) to gather and discuss the im­pending birth. People often share their personal experiences and helpful hints. This ritual may help couples to prepare themselves emotionally and to feel more comfortable.

Increasing knowledge and alleviating anxiety about the birth process are the main concepts behind the Lamaze method of childbirth. In Lamaze, women and their part­ners are taught what to expect during labor and delivery and how to control the pain through breathing and massage. Tension and anxiety during labor have been found to increase pain, discomfort, and fatigue. Many couples feel more prepared and focused af­ter taking these courses.

A few weeks before delivery, the fetus usually moves into a ‘“head down” position in the uterus. This is referred to as engagement. Ninety-seven percent of fetuses are in this position at birth (Nilsson, 1990). If a baby’s feet or buttocks are first (breech position), the physician may either try to rotate the baby prior to birth or recommend a cesarean section. We will discuss this later in the chapter.