Study Links Painkillers To MiscarriagesAug 15, 2003 | San Jose Mercury News Common painkillers like Advil or aspirin can increase the risk of miscarriage in pregnant women by as much as 80 percent, according to a new Kaiser Permanente study published in today's British Medical Journal. But some physicians said that startling finding should be viewed with caution.
Researchers obtained a wealth of data on 1,055 newly pregnant women at Kaiser's San Francisco and South San Francisco medical centers, including their use of painkillers and other drugs, previous miscarriages, smoking and drinking habits, general health, age, ethnicity and income even use of hot tubs.
Women who had taken ``non-steroidal anti-inflammatory drugs'' painkillers like Advil, Motrin and Naprosyn had an 80 percent higher risk of miscarriage than women who avoided these medications, said Kaiser epidemiologist Dr. De-Kun Li, the study's main author. The risk increased if such painkillers were taken shortly before or after conception, or for longer than one week.
The researchers also found a 60 percent higher risk of miscarriage in women who took aspirin, also considered an anti-inflammatory drug, although they cautioned that the small number of women in that category made their data somewhat unreliable. No added risks were seen from Tylenol or similar acetaminophen painkillers.
Obstetricians typically advise women to avoid Advil, aspirin and similar painkillers as well as most other medications because of the potential risk of birth defects. Tylenol is generally regarded as safe during pregnancy.
In this study, the number of women who reported miscarriage after taking the anti-inflammatory drugs was relatively small only 18 so the study's conclusions must be regarded with caution, said Dr. Henry Lerner, a Newton, Mass., obstetrician/gynecologist and author of the recently published book ``Miscarriage, Why It Happens and How Best to Reduce Your Risk.''
``They're doing a lot of (statistical) manipulation on a very small number,'' Lerner said. ``If the findings in this article are valid, it's a very important finding because many women use non-steroidal anti-inflammatory drugs throughout the world. However, I have to be slightly skeptical.''
The researchers did not ask about specific dosages or interview women about their painkiller use before pregnancy. They speculate that anti-inflammatory drugs may increase the risk of miscarriage because they inhibit the release of prostaglandins in the uterus and other organs, which are believed to be necessary for a successful pregnancy. Acetaminophen products also inhibit prostaglandins, but only affect the central nervous system, not the uterus.
Dr. J.T. Parer, a perinatologist at University of California-San Francisco Medical Center, called the study a ``valuable contribution,'' although he wondered whether the women might have taken anti-inflammatory drugs because of some underlying illness that itself could have caused miscarriage. Still, the topic merited more research, he said.
Kaiser researchers plan to follow up with a larger study involving more women, said Kaiser spokeswoman Laura Marshall. Their study is one of the first to examine the link between anti-inflammatory painkillers and miscarriage.
Miscarriage is the loss of a fetus from natural causes before the 20th week of pregnancy. About 15 percent of pregnant women will miscarry, with the majority of miscarriages occurring in the first 12 weeks of pregnancy. Many miscarriages occur because of genetic abnormalities in the fetus. But doctors have identified other risk factors, such as a history of previous miscarriages, smoking, cervical infections and advanced age of the mother.
``I would have totally stayed away from pain relievers as a class if I'd known about the risks,'' said Lynne Mobilio, a Saratoga marketing consultant who is due to give birth in late September. ``You don't want to be shooting yourself in the foot, especially when it's so hard for some women to get pregnant.''