Her Asics laced up and her water bottle at her side, Meredith Dobrosielski stepped onto the treadmill for a robust half-hour walk.
For the Towson, Md., runner, this wasn't just any trip to the gym. The session took place in a lab at Johns Hopkins Bayview Medical Center in Baltimore. Each step offered information on the impact of exercise on her fetus. Dobrosielski is about eight months pregnant.
Doctors expect the information collected to fill in some gaps in the data on how much pounding is okay for a developing baby. Eventually, they hope to be able to develop personalized workout schedules for women in different states of fitness.
"We do know that not only can exercise be done, it should be done," said Dr. Andrew J. Satin, professor and vice chairman of the department of gynecology and obstetrics for the Hopkins School of Medicine. "But the level of fitness should impact the individual's prescription."
Not too long ago doctors used to tell all women not to exercise when they became pregnant, but that advice has changed, said Satin and Dr. Linda Szymanski, a fellow in maternal fetal medicine helping conduct the research. But there still is little data about what's too much for the elite athlete vs. the couch potato and those in between. Satin said much is based on "opinion and common sense."
They believe research is limited because doctors fear testing pregnant women. But nine months into the study, there have been no adverse reactions. As a precaution, the hospital's labor and delivery area is close by.
Lots of benefits
Doctors and groups such as the American College of Obstetricians and Gynecologists and the American Pregnancy Association now give blanket advice to pregnant women to get 30 minutes of exercise a day.
Potential benefits include improvement in general health and a decreased chance of gestational diabetes and hypertension, among others. Also, these groups say, labor, delivery and recovery can be easier.
But the advice is filled with notes of caution for those who are just starting and those with certain conditions. Still, he and others say not everyone has gotten the message that exercise is beneficial.
It was a big change in 2008 when physical guidelines were published for Americans, including pregnant women, said James Pivarnik, of the Center for Physical Activity and Health at Michigan State University.
He said the guidelines do indicate "that the elite runner can continue doing what she is doing for a bit, provided her health care provider is in the loop, and that she has no warning signs or other issues."
Pivarnik agreed more research is needed, such as Satin's.
Good time to start
Szymanski said the incomplete data has only confused the message. "Pregnant women express frustration because a number of doctors give different advice. Some still tell them not to exercise, especially if they haven't been exercising."
Outdated information and myths perpetuated by the Internet still mean many women who had been exercising — up to a quarter by some accounts — stop because they fear they will harm their babies, the doctors said.
Satin said it's a really good time to suggest starting an exercise program. Women are more apt to take care of themselves when they are pregnant. They'll quit smoking, eat better and exercise for the sake of the developing baby and then carry over the good habits, he said.
As long as jogging is comfortable, runners can keep at it. Stationary bikes and running in a pool also are good exercises, Satin said. Walking is safe for nearly everyone.
Dobrosielski, who is about to have her second child, said she decided to participate in the study because she wanted to help other women.
"It's a special population and there's so little time for study," she said. "I felt comfortable exercising, and I knew when I needed to stop. I think it's important for all women to exercise, and maybe this research will convince them to do that."