Some Common Painkillers Linked to Miscarriage Risk
Study Suggests Miscarriage Risk From Using NSAIDs Like Ibuprofen or Naproxen During Pregnancy
One limitation of the study was that it relied on NSAID prescriptions as a marker for their use.
In Canada, one popular NSAID, ibuprofen, is also available over the counter.
As a result, many women in the study who were counted as not taking NSAIDs because they didn't have a prescription might actually have been using them.
Also, getting a prescription doesn't mean that a person actually takes the drug, says Gideon Koren, MD. Koren is a pediatrician, toxicologist, and pharmacologist who directs the Motherisk Program at the Hospital for Sick Children, in Toronto. He was not involved in the study.
Researchers in Sweden, who were looking at the safety of using migraine medications during pregnancy, recently tested the reliability of prescription records by going one step further and interviewing women about their medication use.
They found that many women didn't actually take the drugs their doctors ordered for them. And Koren says that besides their prescription history, there were also important differences between the women who had miscarriages and the women who did not that likely muddied the study's results.
One difference that leapt out at him involved prescriptions for anti-nausea medications, which are sometimes prescribed for morning sickness.
About 15% of the women who didn't have miscarriages got prescriptions for anti-nausea drugs, compared to about 3% of the women who miscarried, a fivefold difference.
"Morning sickness protects against miscarriages," Koren says.
Other differences between the groups were higher rates of depression and anxiety and poverty in the miscarriage group than in the comparison group, though researchers tried to remove the influence of those things by adjusting their data to account for them.
Advice to Women
Taken together, he says he thinks pregnant women should not worry if they have taken an NSAID medication.
"Scaring pregnant women is a national sport in Canada and the United States, and I don't think this is good," Koren says. "It may lead women to not treat themselves when they need it, or even to terminate a wanted pregnancy. I think we have to be extremely careful before we make an association that has major methodological issues."
Study researchers acknowledge that more research is needed to prove that NSAIDs cause miscarriage.
But Bérard says she thinks that in this case, when there are other, perhaps safer choices of pain relievers for pregnant women to use, it's good to get the word out in case the increased risk is real.
"At least during the first trimester, women should think about safer alternatives, and I'm thinking of acetaminophen here," she says. Acetaminophen is the generic name for Tylenol and multiple other medication brands.
Bérard says women can lower their risk of inadvertent exposure by planning their pregnancies.