Eating More Fish Cuts Preterm Delivery Risk

Study says one fish meal a week will do the trick

THURSDAY, Feb. 21, 2002 (HealthDayNews) -- If you've just found out that you are pregnant, one of the best things you might do for your baby is have a tuna fish sandwich. Or cod or scrod or some other fish dish.

A Danish study finds that low intake of fish during pregnancy is associated with a higher risk of premature delivery and low birth weight, both major problems for newborns.

The study, which included more than 8,700 pregnant women, is "the largest ever done," says Sjurour F. Olsen, a senior scientist in the Danish Epidemiology Science Center in Copenhagen, lead author of a report in the Feb. 23 issue of the British Medical Journal.

It doesn't take a lot of fish in the diet to reduce the risk, Olsen says -- one meal a week will produce the protective effect. But even in the fish-eating country of Denmark, a surprisingly large number of women missed that mark.

For example, 11 percent of the women in the study said they never had a hot fish meal; 7 percent said they never ate a fish sandwich, and more than 40 percent said they never ate fish salad. At the other extreme, fewer than 1 percent said they ate fish every day.

The risk of premature delivery and low birth weight was directly related to fish intake, the study finds. It happened for 7.1 percent of the women who never ate fish and for only 1.9 percent of those who ate fish at least once a week.

The reason is not entirely clear, but it probably is related to the omega-3 fatty acids found in fish, Olsen says. Those chemicals are polyunsaturated fatty acids that play a role in the body's production of prostaglandins, which in turn play a role in the widening of the cervix that initiates childbirth, he says.

It's too early to recommend that women eat a lot of fish or take fish oil supplements during pregnancy, says Dr. Michael Katz, vice president for research at the March of Dimes Birth Defects Foundation. "One of the worst possible outcomes is that people get hooked on data and go overboard," he says.

While "there is no harm in eating fish," Katz says, the real story on its value during pregnancy will come from a study that has begun in China, in a region where fish-eating is not common. Pregnant women are being given fish oil and olive oil, and the outcomes of their pregnancies will be recorded. Results are not expected for a while, Katz says.

Showing a beneficial effect of eating fish during pregnancy is "an exciting possibility," Katz adds. "But whether it is real will have to be determined by the prospective study."

What To Do

"There are certain things we do know," Katz says. "A woman should start taking folic acid before she gets pregnant, to prevent neural tube defects. She shouldn't smoke and shouldn't drink during pregnancy. And she should be sure there is good health care supervision for a proper diet, exercise and so on."

A primer on premature, or preterm, delivery, its risk factors and its damaging effects on the newborn is given by the March of Dimes Birth Defects Foundation. The American College of Nurse-Midwives has a page on how a healthy mom makes a healthy baby.

SOURCES: Interviews with Sjurour F. Olsen, Ph.D, senior scientist, Danish Epidemiology Science Center, Copenhagen; Michael Katz, M.D., vice president for research, March of Dimes Birth Defects Foundation, White Plains, N.Y.; Feb. 23, 2002, British Medical Journal
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