The study is one of the first to link use of nonsteroidal anti-inflammatory drugs (NSAIDs) -- such as prescription Motrin, Naprosyn, Voltaren -- during the first trimester of pregnancy to birth defects. But the findings must be confirmed, researchers say, and birth defects experts who were not involved with the study agree.
"If these findings turn out to be true, this is important information because so many women take these drugs early in pregnancy," March of Dimes medical director Nancy Green, MD, tells WebMD.
"About half of all pregnancies in the U.S. are unplanned. Many women don't know they are pregnant until well into their first trimester."
The Canadian study compared 93 births diagnosed with birth defects in 1,056 women who had prescriptions for NSAIDs filled during the first three months of a pregnancy to 2,478 births with birth defects in 35,331 women who did not fill prescriptions for the pain relievers. They looked at records from 1997-2003.
After adjusting for other known risk factors for birth defects, the researchers reported that women who took NSAIDs early in pregnancy were roughly twice as likely to have a baby diagnosed with any birth defect in the first year as women who did not have NSAID prescriptions filled, and they were three times as likely to give birth to babies with a structural defect such as an abnormal opening, or hole, in the dividing wall separating the right and left sides of the heart.
The most commonly prescribed NSAIDs were naproxen, sold by prescription as Naprosyn and over the counter in the U.S. as Aleve; ibuprofen, sold as prescription Motrin or generic ibuprofen and over the counter as Advil and Motrin; and the prescription Cox-2 inhibitor pain relievers Vioxx and Celebrex.
Vioxx and Bextra (another Cox-2 inhibitor) have been withdrawn from the market in the United States due to concerns that their long-term use is associated with an increased risk increase ofand .
Francis Sullivan, a spokesman for Wyeth Consumer Healthcare -- the maker of Advil -- tells WebMD that the "study is based on prescription and not over-the-counter doses."
No significant risk for birth defects associated with other major organ systems was seen in the study, published in the September issue of the journal Birth Defects Research (Part B).
NSAIDs are generally not recommended as the first-line pain reliever of choice duringbecause their use late in pregnancy is believed to increase the risk for another type of birth defect, Green says.
Margaret Honein, PhD, MPH, an epidemiologist with the CDC's National Center on Birth Defects and Developmental Disabilities, says it is clear that more research is needed to determine the safety profile of NSAIDs and many other drugs during pregnancy.
"In general, we know less than we would like to know about most medications, both prescription and over-the-counter," Honein tells WebMD. "Pregnant women and clinical trials, so we often understand very little about a drug's impact during pregnancy when it reaches the market."women are usually excluded from
Honein and CDC colleagues have interviewed 24,000 mothers who gave birth to babies with birth defects since 1998 in an effort to learn more about the causes of congenital abnormalities. The National Birth Defects Prevention Study (NBDPS) is one of the largest research efforts to ever address the issue.
The impact of many different drugs, including NSAIDs, on pregnancy outcomes, is a focus of the study.
"There are many medical conditions that require medication during pregnancy," Honein says. "One of the goals of our research is to try and provide better information to women so that they know the risks, if any."
Until more is known, Honein says, the best advice for pregnant women is to limit medication use to drugs that are absolutely needed.
"Women should not take medications that they don't need during pregnancy, and they shouldn't take a medication without discussing it with their doctor," she says.