No Link Between Heartburn Drugs and Birth Defects: Study

WEDNESDAY Nov. 24, 2010 -- Babies born to women who took a popular class of heartburn drugs while they were pregnant did not appear to have any heightened risk of birth defects, a large Danish study finds.

This class of drugs, known as proton-pump inhibitors (PPIs), include blockbusters such as Prilosec (omeprazole), Prevacid (lansoprazole) and Nexium (esomeprazole). All were available by prescription-only during most of the study period (1996-2008), but Prilosec and Prevacid are now sold over-the-counter.

While the authors and an editorialist, publishing in the Nov. 25 issue of the New England Journal of Medicine, called the results "reassuring," experts still recommend using drugs as little as possible during pregnancy.

"In general, these are probably safe but it takes a lot of time and a lot of exposures before you see some of the abnormalities that might exist," explained Dr. Eva Pressman, professor of obstetrics and gynecology and director of maternal-fetal medicine at the University of Rochester Medical Center. "My recommendations are always to avoid medication exposure if at all possible. There are very few life-threatening disorders that require these PPIs," she noted.

"There are other ways to get the same effect," added Pressman, who was not involved in the study. "Most pregnant women have heartburn but most of it is relatively easy to treat with simple antacids such as Tums and Maalox and Mylanta, all of which are locally acting and absorbed, and don't pose any risk to the fetus."

Even propping yourself up so you're in a semi-vertical position, as opposed to lying flat, can help, said Dr. Michael Katz, senior vice president for research and global programs at the March of Dimes.

The research was funded by the Danish Medical Research Council and the Lundbeck Foundation.

The authors of the new study used linked databases to glean information on almost 841,000 babies born in Denmark from 1996 through 2008, as well as on the babies' mothers' use of PPIs during pregnancy.

PPI use by expectant women was the highest between 2005 and 2008, when about 2 percent of fetuses were exposed, but exposure during the critical first trimester was less than 1 percent.

Babies were followed until they were one year old.

The proportion of babies with birth defects hovered at about 3 percent in both groups -- 3.4 percent of those who had been exposed to a PPI in utero, and 2.6 percent for unexposed babies.

In an unexpected finding, there was a 39 percent increased risk of major birth defects among children whose mothers had taken PPIs in the month before conception, a finding the authors are attributing to either chance or to another factor, perhaps the reason the mother was taking the medication in the first place. This could have been infection with Helicobacter pylori, the bacteria that causes most ulcers.

In addition to Prilosec, Prevacid and Nexium, the authors also looked at Aciphex (rabeprazole) and Protonix (pantoprazole).

Prilosec was the only drug not associated with an increase in birth defects when taken during the month before conception, leading the editorial author to suggest this drug as a first line of treatment.

A related journal editorial, written by Dr. Allen A. Mitchell, director of the Slone Epidemiology Center at Boston University School of Medicine, also noted some caveats. These included the fact that even this big of a sample may not have been large enough to detect specific birth defects (such as heart defects) or to ascertain the effect of specific drugs within the class. Nor can the influence of other factors be ruled out, Mitchell wrote. Perhaps folic-acid supplementation during pregnancy is hiding the true effects of the PPIs, Mitchell said.

The bottom line, according to the experts, is that it's still not clear whether these drugs are safe or not for pregnant women.

"Having negative observations is never absolutely reassuring," Katz said. "All you can say is that within that range [in this case, 800,000 infants], the probability is that it is safe," he explained.

"The balance in pragmatic terms is how important is it to treat the symptoms that any drug is designed to treat versus the safety of pregnancy," he added. "That's a very difficult decision to make."

More information

There's more on pregnancy and birth defects at the March of Dimes.

Posted: November 2010


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