THE PREGNANT BODY
A woman's body undergoes a variety of changes to prepare for the growth, nourishment, and birth of a child. An early sign of pregnancy is the cessation of menses, which results from the rising levels of human chorionic gonadotropin (HCG), a hormone produced by the placenta . Early signs of pregnancy, including breast tenderness, frequent urination, occasional nausea and vomiting (so-called morning sickness), as well as fatigue, are often the first tangible evidence to a woman of the changes that are occurring. These signs generally disappear by 12 weeks of pregnancy. From the first trimester, pregnant women must understand that despite physiologic and anatomic changes they should maintain a safe environment for themselves and the fetus by attention to such details as appropriately wearing seat belts, avoiding alcohol consumption and tobacco, and other potential risks.
In the second trimester, a pregnant woman generally feels energized as the fetus develops within her body. Uterine growth and maternal weight gain are the most obvious manifestations, but complex changes in blood flow volume, cardiac output, and respiratory capacity prepare for fetal growth and the labor and delivery period. The growing fetus begins to press on other organs, and constipation and heartburn may result. Other common occurrences include light-headedness, and normal intermittent uterine contractions, called Braxton-Hicks contractions.
The last trimester of pregnancy is associated with maximal fetal weight gain. Increasing uterine contractions prepare the uterus for the onset of labor. The fetus usually assumes a vertex (head down) position, and the breasts often enlarge and may leak colostrum in preparation for breast feeding. The last weeks of pregnancy may become increasingly uncomfortable because of the woman's increased size.
Headaches, hemorrhoids, varicose veins, and swelling of the legs may occur. Shortness of breath is common because of the enlarged uterus, which prevents full expansion of the lungs. Insomnia may also be common in the days before delivery.
It is widely accepted that women who receive prenatal care have fewer complications of pregnancy and birth and have healthier babies. In addition, the earlier and more consistently the care is received, the better the outcome. Education about pregnancy and child rearing is an important part of prenatal care, as are detection and treatment of abnormalities. The best time to assess many of these risks is before a woman conceives. It is becoming popular for childbearing women to receive preconception care while planning a pregnancy. These preventative visits are designed to achieve optimum health from the moment of conception to birth.
A variety of health-care professionals are involved in providing care to women during pregnancy. These include nurses, nurse-practitioners, nurse-midwives, family physicians, obstetricians, and perinatologists. Most healthy pregnant women with normal pregnancies can receive care from nurse-midwives with appropriate consultation from physicians. Other health professionals such as dietitians and social workers can help provide a safe and healthy pregnancy and birth. However, women at very high risk of complications should be under the care of a physician.