Women who take non-steroidal anti-inflammatory drugs (NSAIDs) during early pregnancy have a slightly higher risk of having babies with certain rare birth defects, according to a new study.
For instance, babies were three times as likely to be born with anophthalmia or microphthalmia if their mothers had taken aspirin or naproxen.
The risk of amniotic band syndrome, a condition that causes various malformations such as clubfoot, was also three times higher when women used NSAIDs during their pregnancy.
It is not clear that the painkillers caused the deformities, however. And even if they did, the risks are minute.
Defects effect is small
These are pretty rare birth defects, so the effect is small, said Dr Eva Pressman, who studies maternal-foetal medicine at the University of Rochester Medical Centre but was not involved in the new work.
A two-fold increase is still rare in the big picture, she told Reuters Health.
According to the Centres for Disease Control and Prevention, anophthalmia and microphthalmia occur in one out of 5,300 births in the US. About one out of 10,000 babies is born with amniotic band syndrome.
The new findings, published in the American Journal of Obstetrics and Gynaecology, are based on data from the National Birth Defects Prevention study. Researchers interviewed women about the drugs they took during the first trimester of their pregnancy. Then they compared 15,000 women whose babies had birth defects and 5,500 women whose babies were free of deformities.
Majority of defects not tied to NSAIDs
"Of the 29 different defects we examined, we were happy that a vast majority were not tied to NSAIDs", said study co-author Martha Werler, from Boston University.
However, a few birth defects were slightly increased in babies whose mothers reported taking ibuprofen, aspirin or naproxen.
For instance, the risk of cleft palate rose by 30% to 80%. And the risk of spina bifida was 60% higher when mothers used aspirin or ibuprofen.
While the results don't prove that painkillers are to blame, Werler said, they are a warning sign and warrant further research.
Dr Pressman said to play it safe, she recommends avoiding NSAIDs during pregnancy.
"For pain I recommend taking Tylenol, which works through a different mechanism of action, and is considered safe for pregnancy", she told Reuters Health.
(Reuters Health, December 2011)