Pregnant women perform fewer intense physical activities, with less duration and frequency than nonpregnant women, and only 16% of pregnant women and 27% of nonpregnant women meet physical activity recommendations, said Ann M. Petersen, Ph.D., and her colleagues at Saint Louis University.
“This study has vital public health implications that can assist physicians to identify patients who are at high risk for inactivity during pregnancy,” the investigators said (Med. Sci. Sports Exerc. 2005;37:1748–53).
“Obstetricians and gynecologists should focus on encouraging continued physical activity during pregnancy among those already active, and should specifically target physical activity promotion among those women performing irregular or no activity,” Dr. Petersen said.
“The message is not getting out that women should continue to exercise during pregnancy, at least at moderate intensity,” study coauthor Terry Leet, Ph.D., noted in a separate written statement. “Only one of every six pregnant women is meeting the current physical activity recommendations of 30 or more minutes of moderate physical activity on most, if not all, days of the week,” Dr. Leet said.
The population-based, cross-sectional study used data from the 1994, 1996, 1998, and 2000 Behavioural Risk Factor Surveillance System (BRFSS) on more than 150,000 women.
A total of 6,528 pregnant and 143,731 nonpregnant women between the ages of 18 and 44 were categorized into groups based on vigorous or moderate levels of exercise, according to guidelines established by the Centers for Disease Control and the American College of Sports Medicine (ACSM). These consisted of 20 minutes or more of exercise, three or more times per week at an intensity of 6 or more metabolic equivalents or METs, and 30 minutes or more, five or more times per week, at an intensity of 3–5.9 METs, respectively; vigorous or moderate activity not meeting the guidelines (150 minutes or more per week, regardless of frequency, at an intensity of 3 METs or more); irregular physical activity; or no physical activity.
The study found that overall, nonpregnant women were more likely to meet the vigorous and moderate exercise recommendations, compared with pregnant women, and more pregnant women were inactive or performing irregular activity.
Walking was the most common activity reported equally by pregnant (52%) and nonpregnant (45%) women. However, there were notable differences between pregnant and nonpregnant women reporting aerobics (8% vs. 14%), and running and/or jogging (2% vs. 7%). Similar percentages reported gardening (3% and 5%) and swimming (4% and 3%).
The findings confirm the need for a multidisciplinary intervention from school educators, medical school instructors, and faculty aimed at promoting exercise in pregnancy, according to Raul Artal, M.D., professor and chair of the department of obstetrics, gynecology, and women's health at the university.
“It has to start at all levels—early school years, medical schools, physician education. A total effort is needed, and it needs to start in childhood,” Dr. Artal said in an interview. “We don't look at physical education as a health benefit but, instead, always seem to emphasize the competitive aspect. If the competitive aspect could be deemphasized, and we could agree that physical education is part of health maintenance and prevention of disease, then the whole attitude toward exercise would change.”
Dr. Artal was lead author of the American College of Obstetricians and Gynecologists 2002 guidelines on exercise during pregnancy.
According to the authors of the study, evidence-based guidelines should be reassuring to health care providers regarding the safety of exercise in pregnancy. The guidelines, published jointly by the Society of Obstetricians and Gynaecologists of Canada, and the Canadian Society for Exercise Physiology in 2003 (and endorsed in 2004 by the ACSM), show that exercise is not associated with any increase in early pregnancy loss, late pregnancy complications, abnormal fetal growth, or adverse neonatal outcomes. The Physical Activity Readiness Medical Examination for Pregnancy in the guidelines describes the medical clearance for prenatal exercise participation.
“These safety procedures will further educate health care providers about the appropriate promotion of exercise during pregnancy,” the authors said.
Researchers say evidence-based guidelines should reassure medical providers of the safety of exercise in pregnancy. Stanford W. Carpenter