The findings suggest that “the message regarding physical activity during pregnancy is not being heard or is not being perceived as important by most pregnant women, although research shows that pregnant women who are physically active are less likely to gain excessive weight during their pregnancy and less likely to develop complications, (such as) gestational diabetes and pregnancy-induced hypertension,” said co-author Dr. Terry L. Leet.

Few studies have investigated the frequency, duration and type of activity that women perform while pregnant, and those that have did not focus on whether the women met the recommended guidelines.

To investigate, the researchers analyzed data collected by telephone in 1994, 1996, 1998, and 2000 from more than 150,000 women, 6,528 of whom were pregnant. All of the women were between the ages of 18 and 44 years old.

Nonpregnant women were more likely than pregnant women to meet the national guidelines for moderate and vigorous activity, the researchers report in the journal, Medicine & Science in Sports & Exercise. “Based on our national survey, only one of every six pregnant women compared to one of every four nonpregnant women are meeting this recommendation,” Leet told Reuters Health.

In 1994, for example, 28 percent of nonpregnant women reported participating in regular vigorous or moderate physical activity, compared with 20 percent of pregnant women. In 2000, 27 percent of nonpregnant women met the guidelines for moderate physical activity, compared with just 16 percent of pregnant women.

Women who meet the recommended physical activity levels while pregnant tended to be younger than their counterparts, nonHispanic white, more educated and unmarried. They were also more likely to be nonsmokers and to have higher incomes, the researchers note.

Overall, walking was the most common activity among the women, reported by 52 percent of pregnant women and 45 percent of nonpregnant women. Fewer pregnant women than nonpregnant women reported participating in aerobics or running/jogging, while gardening and swimming laps were reported by similar percentages of women in both groups.

For each year included in the analysis, however, at least 33 percent of pregnant women reported not participating in any physical activity. Among nonpregnant women, about 25 percent reported participating in no physical activity each year.

“Women are either not choosing to be physically active during their pregnancy because of other demands on their busy lives, or they are not being encouraged by their obstetricians to be physically active,” Leet speculated. “This is a time for pregnant women to make healthy choices that will benefit themselves and their babies.”

The study was funded by the Centers for Disease Control and Prevention.

SOURCE: Medicine & Science in Sports & Exercise, October 2005.