Expectant moms should be active, doctors say

Fanatics and runners who become pregnant for the first time may be shocked to learn that the bible for all mothers-to-be, What to Expect When You're Expecting, has a chapter on exercise that says running for more than 2 miles while pregnant is a no-no. Two miles? For a lot of people, that's a warm-up.

Runner's World's Running for Pregnant Women, on the other hand, tells stories of women who have run marathons while pregnant. That would be 24.2 miles past the other book's recommendation.

When it comes to fitness and pregnancy, there's a lot the experts don't agree on.

Many articles and books say cardiovascular exercise should not exceed 30 minutes at a time and heart rate should be kept under 140 beats a minute. Many experts also seem to suggest that some particular exercises should be avoided: full sit-ups, lunges and bench presses, for example.

But some of those recommendations may be outdated, says Dr. Raul Artal, chairman of the department of Obstetrics and Gynecology at St. Louis University. For the past 25 years, Artal has written the exercise guidelines for the American College of Obstetricians and Gynecologists.

"We abandoned some of those recommendations 20 years ago," he says. "A lot of people are working with old information. The college and I are really publicizing the fact that pregnancy should not be a state of confinement. ...

"Pregnant women should not be deprived of the opportunity to derive health benefits from physical activity. So what we tell pregnant women is that there is no reason to restrict physical activity, unless there are obstetric or medical complications."

Watch temperature

Under the current American College of Obstetricians and Gynecologists guidelines, pregnant women are encouraged to engage in 30 minutes or more of moderate exercise on most, if not all, days of the week.

But what exactly does "or more" mean? Artal says that if a woman physically can do it, it's possible to continue even strenuous exercise for long periods of time throughout pregnancy. However, he says, there are certain precautions.

"One big concern in engaging in strenuous exercise is that if you do this early in pregnancy, you may cause birth defects if your core temperature rises to unsafe levels," he says.

That temperature has to exceed 103 degrees, but if you are running a marathon, it can happen.

Though he has seen plenty of pregnant athletes continue to exercise strenuously, Artal says you get the same benefits during pregnancy by exercising moderately. He recommends that his patients stay away from strenuous activity unless necessary (for instance, if they are professional athletes). "What I tell them is to do the talk test. If they can converse normally while exercising, they are fine."