Too many pregnant women may be taking their physical fitness for granted during their pregnancy, according to a new study.

Researchers found only one in six pregnant women is getting the recommended amount of exercise per week.

The results show that 16 percent of pregnant women get the recommended 30 or more minutes of moderate physical activity on most if not all days of the week compared with 27 percent of nonpregnant women.

“The message is not getting out that women should continue to exercise during pregnancy, at least at moderate intensity," says researcher Terry Leet, PhD, associate professor of community health at Saint Louis University School of Public Health, in a news release.

The American College of Obstetrics and Gynecology recommends that pregnant women exercise with the same safeguards as nonpregnant women provided that there are no complications during the pregnancy.

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Not Exercising

In the study, which appears in the journal Medicine & Science in Sports & Exercise, researchers analyzed data on more than 150,000 pregnant and nonpregnant women who were interviewed by phone in 1994, 1996, 1998, and 2000.

They found only 16 percent of pregnant women and 27 percent of nonpregnant women were meeting the current federal physical activity recommendation by 2000.

In addition, the percentage of pregnant women who said they exercised at a moderate or vigorous level was lower in 2000 than in previous years.

Pregnant women who were meeting their recommended exercise quota were more likely to be younger, white, more educated, nonsmokers, and to have higher incomes.

The study showed that walking was the most common form of exercise among both pregnant (52 percent) and nonpregnant women (45 percent). Other popular activities among all the women surveyed were swimming and aerobic classes.

Researchers say the results suggest that obstetricians and gynecologists need to do a better job at encouraging women without pregnancy complications to exercise.

"These women should be encouraged to begin moderate activities most, if not all days of the week, as long as medical or obstetric complications do not exist," says Leet.

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By Jennifer Warner, reviewed by Louise Chang, MD

SOURCES: Petersen, A. Medicine & Science in Sports & Exercise, October 2005; vol 37: pp 1748-1753. News release, Saint Louis University.