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NSAID Use Around Conception Increases Miscarriage Risk

A study from the American Journal of Obstetrics & Gynecology analyzed pregnant women from the Kaiser Permanente healthcare system and compared newly pregnant women who took non-steroidal anti-inflammatory drugs (NSAIDs) or acetaminophen or neither showed that using NSAIDs around conception carried a more than four-fold higher risk of early miscarriage. (Citation source:

While it is known that NSAIDs should be avoided after week 32 (to prevent premature closure of the ductus arteriosus), there are mixed messages regarding the use of NSAIDs during conception or early pregnancy.

They enrolled pregnant women (N=1,097) who were very early in pregnancy (median gestational age at enrollment was 39 days) to best ascertain fetal outcomes (including miscarriage.  Among eligible women contacted, 63% agreed to participate in the study.

NSAID use during pregnancy was associated with a significantly (59%) increased risk of miscarriage compared to either unexposed controls (adjusted hazard ratio (aHR)=1.59) or 45% increased risk if exposed to acetaminophen use (aHR=1.45). Nearly one-quarter of the women who took NSAIDs had miscarriages within the first 20 weeks of pregnancy, compared with 16 percent of women who took acetaminophen and 17 percent of women who took neither medication.

Most of this risk was evident for NSAID use around conception (aHR=1.89) with a statistically significant dose-response relationship (aHR=1.37) for NSAID use of 14 days or less (aHR=1.85) for NSAID use of 15 days or more.

The association was stronger for early miscarriage (<8 weeks gestational age): aHR=4.08 (95% CI: 2.25 to 7.41). Women with lower BMI (<25) appeared to be more susceptible to the effect of NSAID use around conception (aHR=3.78) than women with high BMI (≥25) (aHR=1.03).

NSAIDs are also among the most commonly used drugs by pregnant women.  These risk may be greater with longer NSAID use as women who used NSAIDs for two weeks or more had more miscarriages than those who took them for less time.

NSAID use around conception was associated with increased risk of miscarriage with a dose-response relationship, especially in women with a lower BMI.


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