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Pregnant women taking common medicines may be at risk, say MED researchers

Effects of Advil, Benadryl and others unknown

A new study showing that pregnant women commonly use over-the-counter medication has spurred a call for more research on the potential of such medicines to cause birth defects.

Led by MED epidemiologist Martha Werler, a research associate professor at the Slone Epidemiology Center, researchers gathered information from more than 7,500 mothers of infants with and without birth defects in the center’s Birth Defects Study. Data were also gathered on more than 2,900 infants with no birth defects from the Centers for Disease Control’s National Birth Defects Prevention Study.

The joint report issued by Slone and the CDC appears in the September 2005 issue of the American Journal of Obstetrics and Gynecology and finds that more studies are necessary to determine the risks and safety of taking over-the-counter medications while pregnant.

“While it is assumed that medication exposures are rare during pregnancy, our study shows that over-the-counter medication use during pregnancy is extremely common,” says Werler. “It is imperative that we obtain empiric evidence of whether such exposures are safe.”

About two-thirds of pregnant women take acetaminophen (the active ingredient in Tylenol) and one in six women takes a decongestant or an ibuprofen-containing product such as Advil.

Researchers say specialized studies are necessary to examine specific over-the-counter medications in relation to specific birth defects. Since such medications do not require a prescription, any identification of associated fetal effects is difficult to track. The only confirmed identification of such effects is between late pregnancy aspirin use and intracranial hemorrhage in the newborn infant.

As aspirin use among pregnant women decreased in the 1980s, the use of acetaminophen increased, researchers found. As acetaminophen use leveled off in the 1990s, ibuprofen use increased after it became available over the counter. This was followed by an increase in naproxen use when it could be purchased without a prescription in 1994.

According to the study’s findings, use of the active ingredients in Tylenol, Sudafed, Benadryl and Robitussin was higher during pregnancy than in the three months prior to pregnancy. While such increases may be because of real increases in upper respiratory symptoms in pregnant women, researchers say it is very possible the changes reflect a relaxed attitude regarding use of nonprescription drugs during pregnancy.

“Internet access, as well as healthcare providers who offer ‘safe-medication lists’ to their pregnant patients could be partially responsible for this pattern,” says Werler. “Women might interpret the receipt of a list of ‘safe’ medications as encouragement for use should symptoms occur, whereas before pregnancy, they might have gone untreated.”