Women who work out regularly or participate in sports are often worried about whether or not they can continue their routine with a baby on board. In most cases, exercise is not only allowed, it's encouraged. Revised exercise guidelines issued by the ACOG in January 2002 recommend thirty minutes of moderate exercise activity daily for women who are pregnant (excluding high-risk pregnancies). All pregnant women, especially those in high-risk pregnancies and those who were inactive prior to pregnancy, should speak with their physician about exercise options.

Vigorous team sports that pose a risk of injury should be avoided (for example, basketball or soccer). Scuba diving is also not advised because of the risk of decompression sickness. However, swimming, walking, and cycling are ideal ways to stay fit. Your local YMCA or community health center may also offer exercise programs geared toward the prenatal set.

Always stay well hydrated when you work out, and try to confine exercise to the coolest parts of the day in the summer months. An excessive rise in core body temperature (hyperthermia), particularly in the first trimester, has been associated with birth defects. If you feel yourself getting warmer than is comfortable, stop your exercise routine and cool down.