What About the Baby?
There are several benefits to the mother if she maintains an exercise program while she's pregnant, but what about the baby? Numerous studies have followed offspring of exercising mothers and have found the babies to be healthy, with normal growth and development.
In an interesting study conducted at the University of Vermont, head researcher James Clapp, MD, matched two groups of pregnant families for socioeconomic status, education, marital stability and body size. The fathers were also included in the body size data.
The two groups were matched for pre- and post-pregnancy exercise habits; both groups of mothers breast-fed, had similar child care arrangements, and had comparable parental weight change over time.
The only difference between the two groups was exercise during pregnancy. One group exercised "vigorously" by running, doing aerobics, cross-country skiing, or some combination of all three. They exercised at least 30 minutes three times per week throughout their pregnancies. The second group ceased all exercise except walking.
The researchers found that by age five, the children of the vigorous exercisers had less body fat than the children born to the walking group. The children born to the second group were called "a bit on the fat side." In addition, the vigorous exercisers' children scored significantly higher on the Wechsler test of general intelligence and coordination as well as on tests of oral language skills.
General Guidelines for Exercise During Pregnancy
Not everyone will be able to maintain a regular exercise program during pregnancy. Some exercise, however, is better than none. ACOG and ACSM revised the recommendations for pregnant women in 2002 to make them less restrictive.
ACOG now suggests that women use their rate of perceived exertion (RPE) as a guideline rather than limiting themselves to a specific heart rate: Generally speaking, if you can carry on a conversation while you exercise, your heart rate is in the right place. This equates to a RPE of 12 to 14, or 60 to 80 percent of aerobic capacity for most pregnant women, according to ACSM (2006).
This guideline may be overly conservative for well-trained athletes. It's important that every woman establish her personal guidelines in consultation with her medical professionals.
For more information on this topic, consult Bicycling for Women by Gale Bernhardt, recently published by VeloPress.
More: Pilates for PregnancySign up for your next Family-friendly race.