November 24th, 2010
05:03 PM ET
Pregnant women who take acid-suppressing medications called proton-pump inhibitors are not at an increased risk of having babies with birth defects, according to a study published in the New England Journal of Medicine. However, an epidemiologist from Boston University School of Medicine, in an accompanying editorial, calls the results "reassuring" but "far from definitive."
"There's no evidence that they do any harm, but we don't yet have as much safety evidence as we would like," said Boston University's Dr. Allen Mitchell. "Unlike experimental studies, a single observational study can't provide definitive results."
Previous smaller studies, including one published in the American Journal of Gastroenterology in 2009, suggested that these drugs can be used safely while a woman is pregnant.
This NEJM study is the largest to date and included more than 840,000 live births in Denmark between 1996 and 2008. The exposure to the proton pump inhibitors ranged from four weeks before conception to the end of the first trimester of pregnancy. The study also included other information such as the history of birth defects in siblings, the mother's use of certain other classes of drugs, smoking status and age at conception. The researchers did not study the reasons why the women were on the medications, nor the use of folic acid, which is widely recognized as playing a role in preventing birth defects.
Proton pump inhibitors are available by prescription and over-the-counter and are taken for symptoms of gastroesophageal reflux or heartburn. The American College of Gastroenterology says symptoms, including discomfort behind the breast bone, a "sour" stomach or pain in the upper abdomen or chest, often are resolved in pregnant women after they give birth.
In the study, of the women who took proton pump inhibitors, 3.4 percent had infants who had major birth defects; in the women who didn't take the drugs, 2.6 percent of infants did.
Mitchell agrees with the study authors that these data provide only a broad and incomplete overview of the most common proton pump inhibitors (omeprazole, lansoprazole and esomeprazole, sold as Prilosec, Prevacid and Nexium, respectively.)
"We know that specific medications in the same group can have different risks for birth defects, so we need more data about specific drugs in relation to specific birth defects," he said, in order to be sufficiently confident about the safety of the drug.
Mitchell pointed to two examples in particular. According to the March of Dimes, pregnant women taking the drug thalidomide in Europe, Canada and other places in the 1950s and 1960s often gave birth to children with missing or shortened limbs. In addition, the drug Accutane has been linked with brain and heart defects.
He stresses that the proton pump inhibitors do not have devastating effects on the fetus as these drugs did, but said that if a pregnant woman believes she needs a proton pump inhibitor, she should talk to her physician first.
“A woman with a chronic gastrointestinal condition who is already on PPIs and who plans to get pregnant should discuss with her doctor any potential risks associated with both her condition and with her medication. Those without chronic conditions and who get pregnancy-associated gastroesophageal reflux, and who are about to take PPI, can take them with confidence that these drugs are not associated with increased risk of birth defects on aggregate,” said study author Dr. Bjorn Pasternak.
The researchers found an unexpected, slight increase in the risk of developing birth defects in women taking proton pump inhibitors other than omeprazole in the period right before conception. But Mitchell says additional studies are needed to study this observation further.
"It may be prudent to consider omeprazole to be the PPI of choice when PPI treatment is clearly needed for women of childbearing potential and particularly for those who are planning to become pregnant," he wrote in the editorial.
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