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Centre de recherche
Tuesday, September 6 2011

Anti-inflammatories taken in early pregnancy more than double risk of miscarriage

Montréal, september 6, 2011 - The risk of miscarriage is 2.4 times greater for women who took any type and dosage of non-aspirin non-steroidal anti-inflammatories (NA-NSAIDs) in early pregnancy, according to a study in CMAJ (Canadian Medical Association Journal).

NA-NSAIDs are a class of drugs that include naproxen, ibuprofen, diclofenac, and celecoxib, and are one of the most common medications used during pregnancy. However, there are concerns about use of these drugs in pregnancy, although studies on the risks have been inconsistent.

Researchers from the University of Montreal, CHU Ste-Justine Research Center, Quebec, and Ecole Nationale de la Statistique et de l’Analyse de l’Information, Rennes, France undertook a study to determine the risk of miscarriage associated with the types and doses of NA-NSAIDs. They looked at a total of 4705 cases of miscarriage up to the 20th week of gestation, 372 (7.5%) of whom took NA-NSAIDs. Of the 47 050 women in the control group who did not miscarry, 1213 (2.6%) of these were exposed to anti-inflammatories. The data came from the Quebec Pregnancy Registry, which provides information on filled prescriptions, physician visits and diagnoses, and hospitalisations during pregnancy.

Women ranged in age from 15 to 45 years old on the first day of gestation and were insured by the Régie de l’Assurance Maladie du Québec (RAMQ) for their medications for at least one year prior to and during pregnancy. Exposure to NA-NSAIDs was defined as having filled at least one prescription for any type of the drug during the first 20 weeks of pregnancy or in the two weeks prior to the start of the pregnancy.

Ibuprofen is the only NA-NSAID available over the counter in Quebec and women in the RAMQ drug plan can have that prescribed as a prescription. Naproxen was the most commonly used NA-NSAIDs followed by ibuprofen.

“This study shows that NA-NSAIDs use during early pregnancy is associated with a statistically significant 2.4-fold increased risk of having a spontaneous abortion,” writes Dr. Anick Bérard, from the University of Montreal and the Director of the Research Unit on Medications and Pregnancy at CHU Ste-Justine. “Our study consistently showed that the risk of spontaneous abortion was associated with gestational use of diclofenac, naproxen, celecoxib, ibuprofen or rofecoxib alone or in combination, suggesting this is a class effect.”

The highest risk was associated with diclofenac alone and the lowest risk was in users of rofecoxib alone. However, dosage of NA-NSAIDs did not appear to affect risk.

These findings are consistent with other studies but are novel with regards to the NA-NSAIDs types and dosages.

“Given that NA-NSAIDs in early pregnancy have been shown to increase the risk of major congenital malformations and that now our study has shown that there is also a class effect on the risk of clinically detected spontaneous abortion, NA-NSAIDs should be used with caution during pregnancy,” the authors conclude.

For information

William Raillant-Clark
International Press Attaché
University of Montreal (officially Université de Montréal)
w.raillant-clark@umontreal.ca - @uMontreal_News

Media contact
Mélanie Dallaire
Senior consultant, Media Relations
CHU Sainte-Justine
Office (514) 345-7707 or 4663 / Pager (514) 415-5727

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Updated on 11/17/2014
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