N onaspirin nonsteroidal antiinflammatory drugs (NSAIDs) are one of the most commonly used medications during pregnancy (17%).1 Nevertheless, gestational use of nonaspirin NSAIDs remains controversial, partly due to the inconsistency of results from studies on their potential risks, the potential for residual confounding by comorbidities and the lack of data on the risks associated with specific types and dosages. [1][2][3][4][5] The strongest association thus far was seen when nonaspirin NSAIDs had been used close to the time of conception, suggesting bias that could be partly explained by women using the drug to alleviate cramping, a precursor to spontaneous abortion. 4 No one has documented the risk of spontaneous abortion according to type and dosage of nonaspirin NSAIDs -both important elements to consider when determining causality.We performed a nested case-control study to quantify the risk of spontaneous abortion associated with specific types and dosages of nonaspirin NSAIDs in a cohort of pregnant women, adjusting for potential confounders.
Methods
Study designWe used a nested case-control study design. We chose this design because it shows similar effect sizes to a prospective cohort approach with timevarying exposure to medication, but with greater computational efficiency.
Data collectionWe used data from the Quebec Pregnancy Registry, an ongoing registry of all pregnancies in Quebec since 1997. Records in the registry are
Use of nonaspirin nonsteroidal anti-inflammatory drugs during pregnancy and the risk of spontaneous abortionHamid Reza Nakhai-Pour MD PhD, Perrine Broy BSc, Odile Sheehy MSc, Anick Bérard PhD The association between the use of nonaspirin nonsteroidal anti-inflammatory drugs (NSAIDs) during pregnancy and the risk of spontaneous abortion remains unclear because of inconsistent research results and the lack of evidence for an effect due to specific types or dosages of nonaspirin NSAIDs. We aimed to quantify the association between having a spontaneous abortion and types and dosages of nonaspirin NSAIDs in a cohort of pregnant women.