NSAIDs don’t increase miscarriage risk

by Bruce Sylvester – Pregnant women who take non-steroidal anti-inflammatory drugs do not increase their risk of miscarriages, researchers report in a study published on Feb. 3, 2014 in CMAJ (Canadian Medical Association Journal).

“The fact that the study was based on large proportion of the district population, was adjusted to nearly all known risk factors for miscarriages (tobacco use, obesity, IVF, uterine malformations, hypercoagulable conditions, intrauterine contraceptive device etc.) and used advanced statistical methods strengthens the validity of the results,” said lead investigator, epidemiologist Prof. Amalia Levy, PhD, Department of Public Health, Ben-Gurion University of the Negev and Soroka Medical Center, both in Beersheba, Israel.

As background, the authors noted that to treat pain, fever and inflammation in the first trimester women often use NASIDs, including ibuprofen, naproxen, diclofenac and others. Prior studies have been inconsistent in assesing the risk of spontaneous miscarriage related to NSAID use.

The investigators evaluated data on 65, 457 women aged 15 to 45 years who were admitted to Soroka Medical Center between January 2003 and December 2009. The subjects either gave birth (90% of women) or had a miscarriage (10%).

Of all subjects, 4495 (6.9%) took NSAIDs during the first trimester of pregnancy.

Notably, the women who used NSAIDs were older, more likely to smoke and had more inflammatory diseases. Also, more NSAID users had undergone in-vitro fertilization (IVF) than  those who did not use NSAIDs.

The researchers reported that about 8.2% of women in the group exposed to NSAIDs had miscarriages compared with 10% of women in the unexposed group.

Among those who took COX-2 selective inhibitors, 17% had a miscarriage. But the group was small and the significance of the data could not be established.

“We found no important associations between exposure to NSAIDs, either by group or for most specific NSAID drugs, and risk of spontaneous abortion,” said the authors. “However, we found an increased risk of spontaneous abortion following exposure to indomethacin.”

The authors hypothesized that since indomethacin is dispensed at the end of pregnancy for treating preterm labor, the finding is distinct from that for other NSAIDS.