Keep Fit but Follow Rules, Pregnant Women Told

For millions of women, exercise is an integral part of the day. But how safe is panting and perspiring during pregnancy? New research suggests that some exercises need to be curbed or even avoided during pregnancy, while others are being recommended right up through the early stages of labor.

“Women who are exercising don’t want to take nine months off to have a baby,” said Dr. Mona Shangold, director of the Sports Gynecology Center at Georgetown University. “And there are really good reasons why women should continue exercising throughout their pregnancy.

“But we need to give some important guidelines so that their activity doesn’t endanger the baby.”

The theoretical risks of exercise to mother and fetus include premature labor, cardiovascular complications, musculoskeletal injuries, congenital malformations or defects and growth retardation.

However, Dr. James Clapp, another leading researcher in the field, emphasized that at the present time, those risks in fact are just theoretical.

No Harm to Fetus

“All the evidence is anecdotal and nothing that could be considered harmful (to the fetus) has been shown to date,” he said.

Clapp, a professor of obstetrics and gynecology at the University of Vermont, is conducting a study that may offer conclusive evidence, but it won’t be finished for at least another two years.

His own past research has revealed that women who exercise throughout their pregnancy appear to gain less weight, recover faster and deliver babies that are “a bit lighter but quite healthy.”

These differences were seen only among women who continued exercising right through their pregnancy. “If you stop exercising at your third trimester, it’s just as though you never exercised at all during your pregnancy,” he said.

“Women who exercise throughout their pregnancy do deliver babies that are about a pound and a quarter lighter than mothers who didn’t exercise,” Clapp said. “That’s the same effect seen in women who smoke two packs of cigarettes a day.”

Less Fat

Before women gasp and swear off aerobics, Clapp said, there is a big difference between the two sets of patients: babies born to exercising mothers show none of the health problems seen in offspring who have shared their mothers’ two-pack-a-day habit.

“These babies (of women who exercise) are a little less fat, that’s all,” he said.

But although there are few proven risks to mother and baby, experts say there are guidelines that should be followed when exercising for two.

For example, Dr. Raul Artal, associate professor of obstetrics and gynecology at USC agreed with Shangold and Clapp but noted: “There are certain limitations, both anatomically and physiologically, which should preclude pregnant women from continuing the same exercise regimen during pregnancy that they maintained in their non-pregnant state.”

First, Artal said, “if you don’t exercise regularly, being pregnant is not the time to start.”

Starting Too Late

“It’s unfortunate that many women become interested in fitness and nutrition for the first time during pregnancy,” Shangold added. They really should get in shape in order to become pregnant and then maintain that (level of fitness) during their pregnancy.” Artal says the best exercises are walking, swimming and stationary bicycling. “The stationary bike is recommended because pregnant women undergo a change in their center of gravity during pregnancy, so they are more prone to losing their balance if they’re riding a standard bicycle,” he said.

“Basically, any type of soft aerobics is excellent for pregnant women,” he said, noting that the ballistic, jerky or bouncing movements of standard aerobic dance should be avoided.

For women not accustomed to aerobic exercise before pregnancy, Shangold suggests limiting activity to nothing more vigorous than brisk walking. For women who are involved in an aerobics program, she suggests continuing “at the same perceived level” of exertion.

“Your actual pace will have to be slower,” she explained. “Merely being pregnant is more work for the body. Add in the extra weight that comes with carrying a baby and you will be able to do less work to get to the same level of exertion.”

There is one exception to Shangold’s rule against initiating any type of exercise program during pregnancy.

Weight Training

“All pregnant women should be involved in weight training programs,” she said. “Even if you haven’t been doing it before (your pregnancy), you should start now.”

A weightlifting regimen, according to Shangold, protects women from many of the muscular aches and pains that often accompany pregnancy.

This advice is contrary to popular belief regarding pregnant women and heavy lifting, but Shangold says: “That’s an old myth which should be put to rest. All women should be engaged in weight training exercise, and pregnant women in particular can benefit from such an exercise program.”

Whatever activities you choose during pregnancy, Shangold suggests monitoring your level of exertion, the duration of your activity and the temperature at which you are working out.

“You should be able to comfortably carry on a conversation (during exercise),” she said.

She also suggests limiting aerobic activity to 30 minutes’ duration. Her concern is two-fold. During exercise, some blood flow is diverted away from the uterus to exercising muscles. This could endanger the baby. Also, exercise can increase internal temperature that can cause certain types of birth defects called neural tube defects.

If a woman prefers extended exercise, Shangold suggests spacing exercise throughout the day in 30-minute increments.

“Also, drink plenty of fluids when you’re exercising, exercise at a cooler time of day and wear light clothing. All of these measures will keep you from getting too hot,” she said.

The American College of Obstetricians and Gynecologists recommends that peak heart rate during activity should not exceed 140 beats per minute for women during pregnancy, Artal said.

“I also stress that we really don’t have any scientific proof that exercise during pregnancy confers anything beyond a feeling of well being. So, if you can’t exercise during pregnancy, don’t feel guilty,” Artal said.

While the benefits and risks of exercise during pregnancy are being debated, new evidence suggests that there may be advantages to exercising during labor.

“In our own studies at USC, we’ve found that exercise during labor can lessen the perception of pain or abolish it altogether,” Artal said.

The USC study specifically examined the pain-relieving abilities of stationary cycling, but Artal noted that simple walking might also be of value.

“We’re talking about the earliest stage of labor when the patient first perceives contractions,” Artal said. “This period can last for three to five hours, and a little exercise can keep you pretty much pain-free.

“Once a patient enters the active stage of labor and the cervix is dilated four centimeters or more, pain perception is there and no exercise will stop it.”