Chapter 11 Summary

  1. The onset of pregnancy is marked by a missed menstrual period and other symptoms. It can be confirmed by urine or blood tests that detect the human chorionic gonadotropin hormone (hCG) secreted by the implanted embryo.
  2. To enhance the chances of pregnancy, coitus should be timed to occur at or just before ovulation. The time of ovulation can be estimated by tracking basal body temperature or changes in cervical mucus or by the use of test kits that detect the surge of luteinizing hormone prior to ovulation.
  3. Infertility or subfertility can be caused by problems in the man or in the woman. If this condition results from a low sperm count or sperm quality, in vitro fertilization may still make pregnancy possible. An alternative is artificial insemination with donated sperm.
  4. Abnormalities of the female reproductive tract, resulting from sexually transmitted infections or other causes, can reduce fertility. The oviducts are the commonest site of such problems. These abnormalities can sometimes be corrected surgically. Alternatively, embryos produced by in vitro fertilization (IVF) can be placed directly in the uterus.
  5. Problems with ovulation can often be treated with drugs. An alternative is the use of donated eggs.
  6. If a woman cannot sustain pregnancy at all, surrogate motherhood and adoption are possible options.
  7. Fertility declines steadily with age in both sexes. Age also raises the likelihood of fetal abnormalities such as Down syndrome.
  8. Many embryos do not survive. Many of those that fail to implant or die early in pregnancy are abnormal. Other conditions, such as Rh factor incompatibility or ectopic pregnancy, can cause fetal loss or harm the fetus or the mother.
  9. Pregnancy lasts about 9 months and is conventionally divided into 3 trimesters. The first trimester may be marked by symptoms such as morning sickness. It is a critical period of fetal development during which the main body plan is laid out and organ systems develop. This process can be impaired by maternal infection or poor nutrition or by use of alcohol, tobacco, or a variety of drugs. Prenatal care offers important benefits, but many women do not receive such care in early pregnancy.
  10. The second trimester is usually easier for the mother. The fetus can be screened for congenital abnormalities and its sex determined at this time. Moderate exercise benefits the mother. The frequency of sexual activity tends to decline during pregnancy, but for most women there is no health reason for abstaining from coitus.
  11. In the third trimester both the parents and the fetus make preparations for birth. Childbirth classes teach strategies to facilitate delivery and to minimize pain.
  12. Labor has three stages. In the first stage, uterine contractions and cervical softening prepare the birth canal for the passage of the fetus. In the second stage, the fetus passes through the canal and is “delivered.” Rapid physiological changes adapt it to an air-breathing existence. In the third stage, the placenta (afterbirth) and fetal membranes are expelled.
  13. Difficult births may necessitate surgical widening of the vaginal opening (episiotomy) or delivery via an abdominal incision (cesarean section). In the United States, episiotomy is performed less often than in the past, but C-sections are increasingly common. Various forms of anesthesia are available if labor is excessively painful. There are also forms of pain relief that do not rely on medications.
  14. Premature or delayed labor is associated with increased risks of harm to the fetus.
  15. The period after birth (postpartum) is a time of recovery for the mother but is marked by depression with disordered thinking in a few women.
  16. The birth of a child, especially a first one, can bring great happiness, but it also causes major stresses. Marital satisfaction tends to decline after the transition to parenthood, and the frequency of sexual activity decreases.
  17. Hormones prepare the mother’s breasts for lactation and mediate the release of milk during nursing. The content of milk changes during the weeks after childbirth. Breast-feeding has significant advantages over formula-feeding, but formula-fed infants can thrive too.