If you are pregnant and you are in a fitness routine, modern science usually says you can keep up your routine within reason. If you have never exercised before, please consult a physician before starting any exercise routine.
There are many reasons to exercise while pregnant. Doctors agree that you need to keep your weight gain to a healthy number, and exercising women tend to gain little body fat during pregnancy. Gaining too much fat during pregnancy can cause extra stress after the baby is born. And she will be too busy tending to a new baby to lose weight right away. Besides that, a breast-feeding woman needs to keep her nutrition level high for the sake of the baby. All in all, not gaining too much is important. Check this approximate calculator to help you find an average for you:
Many doctors discourage running on hard-paved surfaces and some recommend no high impact at all. Many pregnant women find high impact uncomfortable. Actually, riding a stationary bike can be a good alternative for a while, swimming can be very comfortable for the extra tummy weight and walking is always an option. Please remember that the baby needs oxygen, so you should never feel breathless or reach the anaerobic threshold while pregnant.
If you are a mind-body exerciser, make sure that you are doing a routine appropriate for pregnant women. There are many DVDs on the market specifically for pregnant women. Denise Austin has one available on amazon.com. Plank position causes strain on the already-stressed ligaments in the abdomen. This can cause extra tearing of the rectus abdominus, leading to diastasis recti (see my previous article on diastasis recti, as well as the community thread on the subject), so entering your average pilates or yoga class is not recommended.
Weight lifters, the body does benefit from lifting weights. We want your body to be strong for delivery and for taking care of this baby. Again, we don’t want to stress the ligaments in the center of the body and we never want to hold our breath. So keep those things in mind as you lift.