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MONDAY, Feb. 3, 2014 (HealthDay News) -- Pain relievers from the class of medications known as nonsteroidal anti-inflammatory drugs (NSAIDs) won't increase a pregnant woman's risk of miscarriage, according to a new study.
Over-the-counter NSAIDs, such as ibuprofen (Advil, Motrin IB) and naproxen (Aleve), didn't affect the risk of pregnancy loss, Israeli researchers found.
"We did not find an increased risk of miscarriage among women who took those drugs during the first trimester of pregnancy, although we did find an increased risk after the use of indomethacin," said lead author Dr. Sharon Daniel, a pediatric intern at Soroka Medical Center, in Beersheba, Israel.
Indomethacin, a prescription NSAID, was linked to a much higher rate of pregnancy loss, the study found. The prescription drugs known as Cox-2 inhibitors, such as celecoxib (Celebrex), were associated with a slightly higher risk of miscarriage, the study found.
"NSAIDs are frequently and increasingly used by pregnant women both because the drugs are indicated for common symptoms like pain and fever, and because in the past two decades some of the drugs are sold over the counter, without the need for a medical prescription," said senior study author Amalia Levy, an epidemiologist and head of the department of public health at Ben-Gurion University of the Negev in Beersheba.
The findings should reassure women who've taken over-the-counter NSAIDs in early pregnancy, the authors said.
The study authors pointed out that indomethacin is often used as a treatment for preterm labor, and that many of the pregnancy losses associated with indomethacin occurred later in pregnancies. In addition, the average daily doses of indomethacin were higher than for other NSAIDs, according to the study.
As for the increased risk with Cox-2 inhibitors, the authors noted that because they had so few women taking these medications in their study, that their findings need to be confirmed in a larger study.
Results of the study were released online on Feb. 3 in CMAJ (Canadian Medical Association Journal).
Miscarriage is a common occurrence in early pregnancy. About 15 percent of all pregnancies end in miscarriage, according to study background information. Eighty percent of miscarriages occur before the 12th week of gestation, the study authors added.
A number of factors are known to increase the risk of miscarriage, including genetic abnormalities, maternal diseases, obesity, smoking and consumption of alcohol. Several previous studies had suggested that the use of NSAIDs might also increase the risk of miscarriage.
To see if this was true, the researchers reviewed the records of more than 65,000 women who had conceived between January 2003 and December 2009. Just over 6,500 of the women miscarried at some point during pregnancy, according to the report.
NSAIDs were used by 4,495 women at some point in their pregnancy. Ibuprofen was the most commonly used NSAID. Indomethacin was used by 132 women, and Cox-2 inhibitors were used by just 71 women, the study found.
Overall, the risk of miscarriage in women taking non-Cox-2 NSAIDs -- which includes indomethacin -- was increased by 10 percent. When the researchers looked at women taking indomethacin alone, they found a 2.8 times higher risk of miscarriage. For those taking Cox-2 inhibitors, the risk rose by 43 percent, the study reported.
"Our results show that the use of these drugs in the first trimester is not associated with miscarriage," said Levy.
Levy added that this same research group did a previous study that found that NSAIDs in pregnancy didn't increase the risk of fetal malformations either.
However, Levy and Daniel cautioned that NSAIDs shouldn't be taken during the third trimester of pregnancy.
Dr. Jill Rabin, an obstetrician and gynecologist and chief of ambulatory care and women's health at Long Island Jewish Medical Center in New Hyde Park, N.Y., said that whether or not NSAIDs increased the risk of miscarriage was unknown because there haven't been many studies, and those that have been done had conflicting results. She said it was good to see this study's large sample size.
"If a woman has a clinically important reason to take an NSAID, it probably does not increase the risk of miscarriage," Rabin said. "But, it's important to remember that in pregnancy less is more. Most physicians say it's OK to take Tylenol for a headache if you have to. But, don't take anything without your provider knowing. Always discuss anything you take with your provider." (Tylenol is a pain reliever but not a NSAID.)
Learn more about medication use during pregnancy from the U.S. Centers for Disease Control and Prevention.