A new study has indicated that inactive pregnant women can avoid pre-eclampsia by doing stretching exercises rather than walking.
Preeclampsia, also known as pregnancy-induced hypertension, is among the leading causes of maternal and fetal illness and death worldwide.
"These results seemingly contradict the conventional wisdom that walking is the best protection pregnant women have against developing preeclampsia," said Dr. SeonAe Yeo, a women's health specialist at the University of North Carolina at Chapel Hill School of Nursing.
"But for women who were not physically active before becoming pregnant and who have experienced preeclampsia with a previous pregnancy, that might not be the case," she added.
The National Institute of Nursing Research-funded study went on from November 2001 to July 2006, and involved with a previous preeclampsia diagnosis and a sedentary lifestyle.
During the study, the participants were randomly assigned to either the walking group (41 women) or the stretching group (38 women) during the 18th week of pregnancy.
Women in the walking group were asked to exercise for 40 minutes five times a week at moderate intensity, following the program recommended by the Surgeon General and the American College of Obstetrics and Gynecology.
Those in the stretching group were also asked to perform slow, non-aerobic muscle movements with a 40-minute video fives times a week.
With the progression of the pregnancy, the frequency and duration of exercise decreased in both groups.
At the end of pregnancy, the researchers observed that about 15 per cent of women in the walking group had developed preeclampsia, while less than five per cent of women in the stretching group developed the condition.
Yeo pointed out that the incidence of preeclampsia in the walking group was similar to that reported in high-risk pregnancies, while the frequency among the stretching group was similar to rates seen among the general population.
"Clearly, walking does not have a harmful effect during pregnancy. But for women who are at high risk for preeclampsia, our results may suggest that stretching exercises may have a protective effect against the condition," she added.
She said that stretching could provide more protection for the subjects because stretchers produced more transferrin-a plasma protein that transports iron through the blood and protects against oxidative stress on the body-than walkers did.
The researcher believes that her findings may enable prenatal care providers to recommend different exercise plans based on an individual pregnant woman's needs and abilities.
Yeo will make a presentation on her findings at the annual meeting of the American College of Sports Medicine in Indianapolis.
The study is also set to be published in the journal Hypertension in Pregnancy.