Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen and aspirin are implicated in an increasing number of stillbirths among pregnant women, according to a new study.
Compared with other women, those who took NSAIDs were three times more likely to have a stillbirth, the researchers found. That increases risks of stillbirth to women at risk for adverse events due to hormone treatments or medications prescribed for menopause and other conditions.
“NSAIDs are very common medications and should be used appropriately,” said study co-author Stephanie Winston-Woo, a statistician at the American Cancer Society, in a statement. “This study shows that these medications can be found among women at increased risk for stillbirth.”
Patients who are taking drugs for a wide variety of health conditions, such as estrogen replacement therapy or NSAIDs, should “talk to their healthcare provider and avoid taking all of these medications at the same time,” Winston-Woo said.
While the increase in risk in this study seems modest, the researchers caution that it is still a problem. The rate of stillbirths among pregnant women in the United States increased by 60 percent between 1990 and 2010, according to figures from the National Center for Health Statistics.
“I think there is a lot of interest in studies like this but there is not a lot of awareness about what can happen,” said study co-author Charlene Delaney, a statistician at Emory University.
While other studies have connected NSAIDs to stillbirths, a paper published in 2015 concluded that the question of whether one causes the other is “overlooked.”
For the new study, Delaney and Winston-Woo examined data from the National Insurance Birth Cohort, a U.S. Department of Health and Human Services program that follows certain women for up to 38 years to get an estimate of how they may affect the overall birth rate.
Over roughly the same time period, stillbirths among women in the program increased by 55 percent, the researchers reported Thursday in JAMA. In addition, women who regularly took NSAIDs had a 46 percent increased risk for stillbirth compared with women who used them less often.
Aspirin and ibuprofen, at 10 percent and 13 percent, respectively, were the most commonly used NSAIDs. The authors couldn’t account for the link between NSAIDs and stillbirths due to other medical conditions such as uterine fibroids. They can point to evidence that pregnancy is still a medical condition, they say, and it should be treated as such.
The Centers for Disease Control and Prevention recommends that pregnant women avoid taking both NSAIDs and certain oral contraceptives, which can be associated with low birth weight. Other medications that are not indicated for pregnancy, including thyroid medication, can also be harmful.
The authors write that to reduce risks, women who are at increased risk may need to avoid medications that are associated with such stillbirths, such as hormone replacements, cardiovascular medications or endocrine medications.
In an editorial accompanying the study, the authors caution that such a study is unlikely to be the “final word” on the issue. They point out that their results may be skewed by a variety of factors, including women’s preconceptions that a stillbirth might happen and the possibility that factors other than drugs could lead to stillbirths, such as social and cultural factors.
“The greater number of women of reproductive age and greater proportions of nonwhite women on the National Insurance Birth Cohort population were very likely to be affected by even a modest but inescapable increase in stillbirths caused by NSAIDs,” the editorial says.