Swimming is one of the safest and most beneficial forms of exercise during pregnancy. The American College of Obstetricians and Gynecologists (ACOG) specifically recommends it, noting that water workouts use many of the body’s muscles while the water supports your weight, helping you avoid injury and muscle strain. Whether you were a regular swimmer before pregnancy or looking to start something gentle, pool exercise checks nearly every box for prenatal fitness.
Why Swimming Works So Well During Pregnancy
The buoyancy of water is what makes swimming uniquely suited to pregnancy. As your body changes and your center of gravity shifts, land-based exercise can start to feel awkward or uncomfortable. In the pool, the water eliminates much of that uneasiness. It takes pressure off your joints, supports your growing belly, and lets you move freely in ways that might feel impossible on land by the third trimester.
Beyond comfort, swimming delivers real physiological benefits. It relieves pain and muscle spasms, reduces swelling in the legs, ankles, and feet, and helps maintain your range of joint movement. That swelling relief alone is a major draw for many pregnant women, especially in the later months when fluid retention becomes more noticeable. Swimming also provides a solid cardiovascular workout without the jarring impact of running or jumping. Some research suggests aquatic exercise is less stressful on the fetus and doesn’t raise fetal heart rate as much as traditional land-based exercise does.
How Much Swimming Is Recommended
ACOG recommends that pregnant women get at least 150 minutes of moderate-intensity aerobic activity per week. You can break that into 30-minute sessions five days a week, or even shorter 10-minute blocks spread throughout the day. If you weren’t exercising before pregnancy, start with as little as five minutes a day and add five minutes each week until you build up to 30 minutes per session.
Moderate intensity means you’re moving enough to raise your heart rate and break a sweat, but you can still carry on a conversation. If you can’t talk normally, dial it back. If you could sing, push a little harder. That “talk test” is a simple, reliable way to gauge your effort without needing a heart rate monitor.
Pool Temperature and Overheating
One concern that comes up often is whether pool water can raise your core body temperature to unsafe levels. A study of healthy pregnant women found that moderate-intensity aqua-aerobic exercise in pools heated up to 33°C (about 91°F) kept body temperatures within safe limits. Most community swimming pools fall within the 28 to 33°C range (roughly 82 to 91°F), so standard lap pools and even warmer therapy pools are generally fine for moderate exercise.
Hot tubs and very warm soaking pools are a different story. The concern with overheating during pregnancy is that a sustained rise in core temperature could affect fetal development, particularly in the first trimester. A regular swimming pool at normal temperatures doesn’t pose this risk, but you should avoid prolonged soaking in water above 38°C (100°F).
Strokes to Choose and Avoid
Most swimming strokes are safe throughout pregnancy. Freestyle and backstroke tend to be the most comfortable as your belly grows. Backstroke can feel especially good because it takes all pressure off your abdomen, though some women find lying on their back uncomfortable in later pregnancy.
Breaststroke deserves a specific mention. The wide kicking motion can aggravate pelvic girdle pain, a common pregnancy condition where the joint at the front of the pelvis becomes inflamed and tender. If you notice pain or discomfort in your pelvis during breaststroke, switch to a different stroke or use a pull buoy between your legs to eliminate the kick entirely.
Chlorine and Chemical Exposure
Many pregnant women worry about whether chlorinated pool water is safe. There are no published studies on the effects of chlorine exposure from swimming pools on human pregnancy. Some research has looked at chlorination byproducts in drinking water and found inconclusive links to certain outcomes like preterm delivery, but the exposure level from swimming in a pool is very different from long-term ingestion through tap water. Standard chlorinated pools are considered safe for pregnant swimmers.
Scuba Diving Is Off Limits
Surface swimming is safe, but scuba diving is not. The Divers Alert Network advises against diving during pregnancy because the pressure changes involved increase the risk to the fetus, and the consequences can be serious. Decompression creates conditions that a developing baby cannot safely handle. Beyond the fetal risk, pregnancy-related changes like swollen sinuses can make equalizing ear pressure difficult, and nausea can worsen underwater. A growing abdomen also makes fitting into dive equipment problematic. Snorkeling at the surface is fine, but anything involving compressed air and depth should wait until after delivery.
When to Stop and Get Out
If swimming causes uterine cramping every 10 minutes, stop immediately and contact your obstetrician. If the cramping continues even after you’ve left the pool, call your doctor’s office right away. Vaginal bleeding, dizziness, shortness of breath that doesn’t improve with rest, or feeling faint are all signals to stop exercising.
One situation where swimming becomes off limits entirely is if your water has broken. Once the amniotic sac ruptures, the protective barrier between your baby and the outside environment is gone, and exposure to bacteria in pool water or natural bodies of water poses an infection risk.
Preventing Infections After Swimming
Pregnancy increases your susceptibility to urinary tract infections, and sitting in a wet swimsuit doesn’t help. Change out of your swimwear as soon as you’re done in the pool and put on dry, cotton underwear. Empty your bladder completely before and after swimming, drink plenty of water throughout the day (six to eight glasses), and avoid tight-fitting clothing that traps moisture afterward. These simple habits significantly reduce your risk of both UTIs and yeast infections, which are more common during pregnancy due to hormonal changes.
Open Water vs. Pool Swimming
Pools offer a controlled environment with consistent temperature, no currents, and easy exit points, which makes them the safer choice during pregnancy. If you prefer open water, be aware that lakes, rivers, and oceans carry higher bacteria levels, unpredictable temperatures, and currents that can tire you faster than expected. Your balance and stamina change throughout pregnancy, so conditions that felt manageable before may not be safe at 30 weeks. If you do swim in open water, never go alone, stay in shallow areas where you can touch the bottom, and avoid cold water that could cause cramping or shock.