You've probably seen the videos or at least heard the stories of women a month or two away from delivery and still pumping iron and running marathons. These pregnant phenoms elicit as much admiration as they do concern from onlookers.
If you're a mom-to-be bent on keeping up your workout routine, the trick is to consult your doctor, know your limit and have a plan for each trimester.
"Pregnancy should not be a state of confinement," said Raul Artal, chairman of the department of obstetrics, gynecology and women's health at Saint Louis University School of Medicine. "Healthy pregnant women should stay active, but take into account that their bodies change during pregnancy."
Artal, an author of the American College of Obstetricians and Gynecologists' guidelines on exercise during pregnancy, advises women to maintain their current level of training, whether it's biking, running or lifting. If you were squatting 125 pounds before donning maternity wear, then you can probably keep it up as elastic-waist pants take over your closet.
You may have to lower the weight as the pregnancy progresses, however, if you start developing back pain. It's common for pregnant women to suffer from lordosis, a curvature of the spine that can cause lower back pain during strength training, Artal said.
Proper technique is essential to prevent injury, especially at the tail-end of the pregnancy when your body will have a buildup in relaxin, a hormone that loosens ligaments for an easier delivery, said Michelle Mottola, director of the R. Samuel McLaughlin Foundation-Exercise and Pregnancy Lab at the University of Western Ontario.
Joints might be prone to injury because of the higher hormone levels. So it's best to cut out any exercises that require rapid changes in direction or bouncing -- no split jumps or burpees. And isometric exercise -- the sorts of moves that require hold periods -- is best left for post-pregnancy workouts.
Stick to static moves such as squats, which are good for strengthening your abdominals and pelvic floor, the muscles and ligaments that support the womb, said Lisa Reed, a Washington-based trainer.
She designs fitness and nutrition programs for each trimester of pregnancy and post-delivery.
"The biggest thing with prenatal clients is strengthening the pelvic floor and abdominals," Reed said. "Abdominals are going to be vital to carrying the baby, to your posture and to the pushing stages of labor."
Reed also encourages clients in the third trimester to sit on the floor with a stability ball behind their back, pushing against the ball and taking deep breaths in and out.
"As you exhale and push your lower back in, you are actually using your abs to exhale," she said. "Pregnant women have to be really conscious of their breathing and remain hydrated throughout their workout."
Mottola recommends that women hold off on heavy lifting, instead use lighter weights with higher counts, say 12 to 15 repetitions per set.
Save the maximum reps and power lifting for after you deliver your bundle of joy to avoid putting too much pressure on your joints, Mottola said.
There are some exercises that you should avoid at certain points during your pregnancy.
Exercising while lying on your back is a no-no past four months, Mottola said. Your enlarged uterus could either decrease the flow of blood returning from the lower half of your body as it presses on a major vein or decrease the flow to a major artery.
Reed said she advises her pregnant clients to avoid exercises such as knee lifts and high kicks that shift the pelvic floor.
Anything that "puts more stress on the pelvic floor and twisting of the body is not advised in the third trimester," she said.
On the other hand, swimming or any kind of exercising in the water is a great way for women to stay in shape throughout their pregnancy, Reed said.
Buoyancy alleviates some of the joint stress moms-to-be experience, and lap swimming can help condition muscles.