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Study finds that use of nonaspirin NSAIDs during pregnancy may increase the risk of miscarriage

Sept. 6, 2011

By Maria Serraino

A new study found that taking nonaspirin nonsteroidal anti-inflammatory drugs (NSAIDS) in early pregnancy more than doubled the risk of miscarriage.

NSAIDS are used to treat pain, fever and inflammation, and are among the most commonly used medications during pregnancy.  However, the use of nonaspirin NSAIDs is controversial because it’s not clear whether they are risky in pregnancy, and there isn’t a lot of research on specific  types and dosages. 

Researchers at the University of Montreal designed a nested case-control study to quantify the risks of miscarriage before 20 weeks’ gestation.

They used data from the Quebec Pregnancy Registry on 4,705 women, between the ages of 15 and 45, who had a miscarriage.   Each of these women was then matched to 10 controls, resulting in a control group of 47,050 women.  Controls were randomly selected from pregnant women who did not have a miscarriage but who were at the same gestational age of their matched case. 

The researchers then used prescription data to compare nonaspirin NSAIDs in the control group and the miscarriage group, using the two weeks immediately before the miscarriage as a window for exposure.  They also examined the dose-response relationship and associations between different types and dosages. 

After adjusting for factors such as recent illness,  the use of other medications suspected of increasing the risk of miscarriage, and a history of previous miscarriage, the researchers found that use of nonaspirin NSAIDs during pregnancy was significantly associated with the risk of miscarriage. 

The rate of nonaspirin NSAID use among women who had miscarriages was much higher than in the control group: 7.5 per cent, compared to 2.6 per cent in the control group. 

The study found that the use of nonaspirin NSAIDs during early pregnancy is associated with statistically significant risk (2.4-fold increase) of having a miscarriage. 

Specifically, the use of naproxen, ibuprofen, celecoxib (such as Celebrex), diclofenac (such as Voltaren) and rofecoxib (such as Vioxx), alone or in combinations, were all associated with increased risk of miscarriage.  However, no dose-response relationship was seen. 

The researchers recommend that these drugs be used with caution during pregnancy. 

The study was published in the Canadian Medical Association Journal on Sept. 6, 2011.

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  • A publication of:
  • Women's College Hospital