Barbara Dehn, RN, MS, NP, author of Your Personal Guide to Pregnancy, also prefers her clients avoid the stair climber, explaining that there may be pain in the round or broad ligaments due to the legs going up and down and pulling on the ligaments. "Because the ligaments around the uterus stretch so much, some women may have some discomfort; and those ligaments get stretched anyway so that might just exacerbate it," Dehn says.
Squats should also be avoided, Dehn says, because of both the weight of the uterus and the gravitational and exertional pressure on the pelvic floor. She adds that increased pressure on the bladder can increase the likelihood of hemorrhoids and even incontinence.
Prenatal personal trainer Anna Ostashevskaya-Gohstand tells her clients to avoid "any exercises that involve double-leg raises and full sit-ups, as they can lead to diastasis recti (abdominal muscle separation)." She also advises them to stay away from adductor/abductor machines since, if used improperly, they can cause problems and pain at the symphysis pubis—the joint connecting the two halves of the pelvis. And lastly, Dehn adds that if you're past your fifth month of pregnancy you should avoid exercises on your back; lying on your side is your best bet.
Free Weights or Machines?
Pregnancy should not hinder you from enjoying your regular weight-lifting regimen, minus some of the intensity. As you get bigger in the middle and more unbalanced, the exercises you were doing pre-pregnancy may not be as safe. Decreasing the weight and doing more repetitions (12 to 15) is advised, Dehn says, as long as you're comfortable with the free weights and doing the exercises properly.
Dehn also encourages her patients to continue upper-body exercises during pregnancy because a strong upper body will be helpful once you have a growing baby (and infant seat!) in tow.
Free-weight exercises done sitting in a chair with back support such as bicep curls, lateral shoulder raises, and triceps overhead extensions are all good upper-body choices. Make sure you are breathing steadily and not holding your breath.