Women who are trying to conceive should not take two aspirin and call their doctor in the morning, according to a new study. It shows that aspirin and ibuprofen, but not acetaminophen, taken around the time of conception almost double the risk of miscarriage. The results may change the way doctors recommend over-the-counter painkillers to pregnant women.
About 15% of pregnancies end in miscarriages, and physicians know little about what factors put women at greater risk. A study last year suggested a link between a class of painkillers called nonsteroidal anti-inflammatory drugs (NSAIDs) and miscarriages. NSAIDs, which include common painkillers such as ibuprofen and aspirin, reduce pain by purging prostaglandins, which fertilized eggs need to plant themselves in the womb.
To test whether NSAIDs rattle pregnancies, a team of researchers led by reproductive epidemiologist De-Kun Li of the Kaiser Foundation Research Institute in Oakland, California, interviewed 1055 women who had conceived within the previous 40 days. They asked about painkiller use around the time the women were trying to get pregnant and followed the pregnancies in women who were successful. The researchers took into account activities such as drinking coffee or hot-tubbing and excluded women at risk for miscarriages in the absence of treatment, such as women who reported cramping.
The risk of a miscarriage was 80% higher than usual for women who took aspirin or ibuprofen (the active ingredient in Advil) regularly for more than a week, the team reports in the 16 August issue of the British Medical Journal. Acetaminophen (the active ingredient in Tylenol) didn't affect pregnancies at all. The risk jumped dramatically if women took the drugs within a week of conception: Five times the number of women taking either of the two NSAIDs had miscarriages, compared to women who took nothing or took acetaminophen. Ultimately, Li says, the Federal Drug Administration will have to decide on whether to reclassify aspirin and ibuprofen. Li notes that newer NSAIDs, such as COX-2 inhibitors like Celebrex, have been tested for reproductive effects and are not recommended for pregnant women.
Epidemiologist Gunnar Nielsen of Odder Hospital in Denmark says the study shows "almost beyond doubt" that NSAIDs will make it more difficult for some women to get pregnant. "If pregnant women need painkillers during pregnancy," he suggests, "they should ask their doctor if [acetaminophen] will be sufficient."