Most exercise during pregnancy is not only safe but recommended. The real list of exercises to avoid is shorter than you might expect, and it centers on a few specific risks: impact to the abdomen, overheating, joint instability, and restricted blood flow. Knowing which movements and activities fall into those categories lets you stay active with confidence.
Contact Sports and High-Impact Activities
Any sport that carries a real chance of a hit to your abdomen is off the list for the duration of pregnancy. That includes basketball, soccer, ice hockey, kickboxing, and martial arts. It also covers activities where a fall is likely, such as downhill skiing, horseback riding, surfing, and gymnastics. The concern isn’t just a direct blow to the belly. As your center of gravity shifts forward, your balance changes, and activities that rely on quick direction changes or uneven surfaces become riskier than they were before.
Scuba diving is a firm no at any stage of pregnancy. The pressure changes underwater create gas bubbles in the bloodstream, and a developing baby’s circulatory system cannot filter those bubbles the way an adult’s lungs can.
Why Your Joints Are More Vulnerable
During pregnancy, your body produces a hormone called relaxin that loosens muscles, joints, and ligaments, particularly around your pelvis, back, and abdomen. This loosening helps your body accommodate a growing baby and eventually give birth, but it also makes you more prone to sprains and overstretching. You may notice this as instability when climbing stairs, getting out of a car, or standing on one leg.
Because of relaxin, exercises that push your joints to their end range are riskier than usual. Deep squats with heavy weight, plyometric jumping, explosive Olympic lifts, and aggressive stretching can all strain ligaments that are already more lax than normal. You don’t need to avoid strength training entirely. Just dial back the load, control each movement, and skip anything that feels unstable.
Exercises That Strain the Abdominal Wall
As your uterus expands, the two sides of your outermost abdominal muscle can separate along the midline, a condition called diastasis recti. Any movement that forces the abdominal wall to bulge forward can make this worse. After about 12 weeks of pregnancy, you should avoid:
- Crunches and sit-ups of any kind
- Standard planks and push-ups without modification
- Double leg lifts and scissors from Pilates
- Certain yoga poses like boat pose and full downward dog
A quick visual test: if your belly cones or domes outward during a core exercise, that movement is putting too much pressure on the separation. Modified side planks, pelvic tilts, and diaphragmatic breathing exercises are safer alternatives that still keep your core engaged throughout pregnancy.
Lying Flat on Your Back
Starting around the midpoint of the second trimester (roughly 20 weeks), lying flat on your back during exercise can cause problems. The weight of your uterus compresses the large vein that returns blood to your heart, potentially reducing blood flow to both you and the baby. This is called supine hypotensive syndrome, and it affects up to 15% of women at full term.
In practical terms, this means traditional bench presses, floor-based ab work, and any exercise where you’re flat on your back for more than a brief moment should be modified after about 20 weeks. Inclining a bench to at least a 30-degree angle or switching to side-lying positions solves the problem without requiring you to drop the exercise entirely.
Hot Yoga and Overheated Environments
Raising your core temperature above 102°F, or more than 3°F above your resting temperature, has been linked to abnormal fetal development, particularly in the first trimester. Hot yoga studios typically run around 95 to 105°F with high humidity, which is the concern.
Research on pregnant women in heated yoga classes found that their core temperatures stayed within a safe range, peaking at about 100°F, which suggests the risk may be lower than once feared for well-hydrated, acclimated individuals. Still, the margin for error is slim. Exercising in extreme heat, whether that’s a hot yoga class, a sauna, or outdoor running in midsummer, reduces your body’s ability to cool itself. Regular-temperature yoga, swimming, and climate-controlled gyms are straightforward ways to avoid the issue altogether.
High-Altitude Exercise
If you’re not already acclimated, exercising above about 8,250 feet (2,500 meters) can reduce oxygen availability for both you and your baby. At altitude, your heart rate rises faster, you fatigue sooner, and your body is already working harder to deliver oxygen to the placenta. If you’re traveling to a mountain destination, avoid strenuous exercise for the first four to five days and stay at a lower elevation for workouts during that adjustment period. Women who live at altitude year-round generally adapt and face less risk.
How to Gauge Your Intensity
You may have heard the old rule about keeping your heart rate under 140 beats per minute during pregnancy. That blanket number has been dropped from current guidelines because resting heart rates vary so much from person to person. Instead, the recommended approach combines two tools: a perceived exertion scale and your actual heart rate.
On a scale of 6 to 20 (where 6 is no effort and 20 is maximum), moderate-intensity exercise falls between “fairly light” and “somewhat hard,” roughly 12 to 14. In heart rate terms, that corresponds to about 60% to 80% of your age-predicted maximum. The simplest test: you should be able to carry on a conversation while exercising. If you’re gasping between words, you’ve crossed from moderate into vigorous territory and should ease back.
Current guidelines recommend at least 150 minutes of moderate-intensity aerobic activity per week during pregnancy. That target is a floor, not a ceiling. Many women safely do more, but the key is staying in that moderate zone rather than pushing into high-intensity intervals or all-out sprints, especially if you weren’t training at that level before becoming pregnant.
Signs to Stop Immediately
Some warning signals during exercise call for stopping right away: vaginal bleeding, fluid leaking from the vagina, dizziness or feeling faint, chest pain, calf pain or swelling (which can signal a blood clot), regular painful contractions, and shortness of breath before you’ve even started moving. These aren’t signs to “push through.” They’re signs something needs medical attention.
Beyond those red flags, trust what your body is telling you. Pregnancy changes your baseline week by week. An exercise that felt great at 16 weeks may feel wrong at 28, and that shift is normal. Modifying or swapping out movements as your body changes isn’t scaling back. It’s training smart.