SOURCES: Thierry Buclin, M.D., Swiss Teratogen Information Service and division of clinical pharmacology, Lausanne University Hospital, Switzerland; Page B. Pennell, M.D., associate professor, neurology, Harvard Medical School, Boston; Steven Danehy, spokesman, Pfizer, Inc.; May 18, 2016, Neurology, online
WEDNESDAY, May 18, 2016 (HealthDay News) -- The widely prescribed drug pregabalin (Lyrica) may slightly increase the risk for birth defects, a new study suggests.
In a small study, researchers found that among women taking Lyrica during the first trimester of pregnancy, 6 percent had infants with major birth defects. In women who weren't taking the drug, 2 percent had a baby with a major birth defect, the study found.
"These results should be taken with caution," said study senior author Dr. Thierry Buclin, from the Swiss Teratogen Information Service and the division of clinical pharmacology at the Lausanne University Hospital, in Switzerland. "It's a warning, but it cannot be taken as a certainty."
Lyrica is prescribed for a range of health problems, including epilepsy, fibromyalgia and anxiety.
The new study findings should be investigated further, Buclin said. "We should not unduly alarm mothers-to-be about a definite risk. This is just a signal, a warning that there might be a problem with Lyrica," he said.
Experiments in animals have also linked Lyrica to birth defects, Buclin said. "But there are many examples of drugs showing an adverse effect, which turn out to be rather safe in humans," he explained.
Buclin doesn't currently recommend Lyrica for women who are thinking about becoming pregnant.
Steven Danehy, a spokesman for Pfizer Inc., the maker of Lyrica, said, "The study has significant limitations and cannot be used to draw definitive conclusions."
The study was small, did not account for other medical conditions or medications, "and the women taking Lyrica had higher rates of smoking and diabetes, all of which can negatively affect pregnancy outcomes," Danehy said.
The report was published online May 18 in the journal Neurology.
Lyrica is approved by the U.S. Food and Drug Administration to treat epilepsy, fibromyalgia and neuropathic pain, such as pain from diabetic neuropathy or pain after shingles or spinal cord injury, according to the prescribing label information. In addition, doctors prescribe it "off label" for anxiety and other mental health problems, the study authors said.
The study included 164 women who took Lyrica during their first trimester of pregnancy. Researchers compared these women to a group of 656 pregnant women who didn't take Lyrica.
Among the women taking Lyrica, 115 used it to treat neuropathic pain; 39 took it for depression, anxiety, bipolar disorder or psychosis; five were taking it for epilepsy; and one for restless legs syndrome.
Most of the women taking Lyrica started taking it before they became pregnant but stopped taking the drug an average of six weeks into their pregnancy, the researchers said. Twenty-two of these women were also taking another anti-seizure drug.
Birth defects linked to Lyrica included heart defects and problems with the central nervous system or other organs. Women taking Lyrica were six times more likely to have a baby with a major defect in the central nervous system than women not taking the drug, the researchers said they found.
At least one physician said it's probably best to avoid Lyrica if you're planning to get pregnant until more is known about the drug's effects.
"The risk of birth defects is probably higher with Lyrica," said Dr. Page Pennell. She is an associate professor of neurology at Harvard Medical School in Boston, and coauthor of an accompanying journal editorial.
"It's that we just can't prove that with this study," she said. "This is probably the best information we are going to get, and there is a signal of concern here."
Because many anti-seizure drugs can cause birth defects, it's important to plan pregnancies, Pennell said. "If you have a planned pregnancy, it gives the woman a chance to discuss with her doctor the pros and cons of staying on a medication," she said.
But, some women may need to stay on Lyrica while pregnant, Pennell said. Any potential risks associated with the drug need to be "weighed against the need to maintain maternal disease control," she wrote.
Buclin and Pennell both recommended careful monitoring of the pregnancy if a woman takes Lyrica while pregnant.
Pennell said birth defects can start very early in pregnancy. "So you cannot wait until you have a positive pregnancy test and think about whether a drug is safe during pregnancy," she said.
Learn more about birth defects from the U.S. Centers for Disease Control and Prevention.