The study, reported in the journal Obstetrics & Gynecology, looked at the possible connection between miscarriage and non-steroidal anti-inflammatory drugs (NSAIDs) - which include common painkillers like aspirin, ibuprofen (Advil, Motrin) and naproxen (Aleve, Naprosyn).

Some studies have hinted at an increased miscarriage risk among women who use NSAIDs around the time they conceive or in early pregnancy. But other studies have failed to find a connection. Much of the evidence suggesting a risk has been based on prescription NSAIDs, said Digna Velez Edwards from Vanderbilt University in Nashville, who led the new study. But most women of childbearing age use over-the-counter NSAIDs, for occasional aches and pains.

So Edwards and her colleagues looked at over-the-counter NSAID use among nearly 3,000 pregnant women who were part of a larger study. Overall, 43 percent said they'd used the painkillers at some point around the time they conceived or in their first six weeks of pregnancy.

Thirteen percent of all women suffered a miscarriage during the study. But the risk was no greater for women who'd used NSAIDs, regardless of the number of days they took the drugs, Edwards's team found. "Our study would suggest that over-the-counter doses of NSAIDs are not associated with miscarriage," Edwards told Reuters Health.

On the other hand, she said, "we can never know whether NSAIDs or any other medication are completely safe for pregnant women."

That's because ethically, researchers can't do clinical trials where they randomly assign pregnant women to take a medication or not. Instead, they have to rely on studies like this one, which have a number of limitations - like relying on women's memories and ability to accurately report their NSAID use.

The new study was partly funded by the National Institutes of Health. None of the researchers reports any conflicts of interest. There are biological reasons to believe that NSAIDs could pose a miscarriage risk, Edwards said.

NSAIDs affect hormone-like substances called prostaglandins. And it's possible they could interfere with the normal prostaglandin changes that happen early in pregnancy. But no one knows for sure.

Despite the new findings, it's not clear whether NSAID use in early pregnancy is completely safe. Some studies have hinted that the medications are related to increased risks of certain birth defects.

In general, experts recommend women limit their medication use during pregnancy, if possible. And it's thought that acetaminophen (Tylenol) is the safest option for occasional pain relief during pregnancy.

Edwards said women who are pregnant, or trying to get pregnant, should ask their doctors about all medication use, including over-the-counter painkillers.

SOURCE: bit.ly/LNknuw Obstetrics & Gynecology, July 2012.

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