Swimming is excellent exercise for pregnant women: Not only does it provide an aerobic workout, the buoyancy of water while you're swimming helps soothe some of the aches and pains of your expanding body. While the pool generally is safe for pregnant women, if you want to take a dip in the lake instead, you should take a few precautions, and as with other pregnancy questions, check with your health care provider to make the best decision for you.
Temperature
On hot days, lake water temperatures can rise to unsafe swimming temperatures for pregnant women. Check with the park services department if your lake has one, or bring your own thermometer to make sure the water temperature is lower than 84 degrees F, the hottest recommended water temperature for pregnant women, according to USA Swimming. Swimming in too-warm water can dangerously elevate your body temperature, a condition that's associated with increased risk of birth defects, especially during the first trimester.
Contamination
Lakes are more likely than swimming pools to harbor bacteria that can cause infection since the chlorine in swimming pools kills most harmful bacteria. Illnesses caused by water-borne bacteria, called recreational water illnesses, can come in the form of mild-to-severe stomach and intestinal problems, rashes and skin irritation, or serious respiratory health issues, explains the Washington State Department of Health. For pregnant women, these issues might affect the health of your baby as well as you. Check with your state's environmental agency or the U.S. Environmental Protection Agency to learn about dangerous bacterial levels or beach closings in your area, and swim only in the part of the lake designated for swimmers to reduce your risk.
Difficult Swimming
Swimming typically is safe throughout your pregnancy, but remember that you'll tire more easily as your pregnancy progresses and take that into account if you're planning a lake swim. Keep in mind that swimming in a lake can be more difficult than swimming in a pool because of currents, and that it's easy to underestimate distances. Swim with a partner so that you'll have assistance if you need it, and stay within easy swimming distance of the shore in case a sudden storm comes up.
General Concerns
Pregnant women should take certain precautions wherever they swim. Don't jump in the water; instead, ease your way in by walking down the shoreline. Make sure to drink plenty of water so that you stay hydrated during your swim, especially during hot, humid weather; aim to get one cup of water for every 20 minutes of swimming and one cup before and after your swim, recommends James M. Pivarnik of Michigan State University, on BabyCenter.com. Always check with your doctor before starting any exercise during pregnancy: Though swimming generally is safe, your health care provider might recommend you avoid it if you have certain pregnancy complications, such as cardio-pulmonary health issues or ruptured membranes.
