In addition to the debilitating joint disorder gout, the inflammation-fighting drug colchicine has been used for decades to prevent and treat familial Mediterranean fever, a rare genetic condition that mostly strikes people of Jewish, Armenian, Arabic or Turkish ancestry, Dr. Asher Ornoy of the Hebrew University Hadassah Medical School in Jerusalem and colleagues explain.

The disease leads to bouts of inflammation and fever, and may increase a woman's risk of miscarriage and preterm delivery; treatment with colchicine can improve women's ability to carry a child to term.

Because colchicine crosses the placenta, and has been linked to birth defects in some animal studies, concerns have been raised that it could be harmful in pregnancy, especially since it may affect cell division, Ornoy and colleagues note.

Studies in humans have been "reassuring" but small or have not included comparison groups, they further point out in the American Journal of Obstetrics & Gynecology.

To get a better sense of whether the medication is risky for pregnant women, the researchers looked at 238 women who had taken colchicine during their pregnancies and 964 women who had not, and were not exposed to any other potentially harmful medications.

Among the women taking colchicine, 97 percent used it during the first 3 months of pregnancy, while 80 percent took the medication throughout pregnancy. Nearly 90 percent were taking colchicine for familial Mediterranean fever, 8 percent for Beh�et disease (an autoimmune condition also common among people of Mediterranean descent), and the rest for other causes. Fewer than 1 percent were using the drug to treat gout.

In the colchicine group, 4.7 percent of babies were born with major birth defects, such as heart malformations, compared to 3.2 percent of the babies not exposed to colchicine. This was not a statistically significant difference, meaning it could have been due to chance. None of the babies born to women taking colchicine had chromosome-related birth defects such as Down syndrome.

However, babies whose mothers took colchicine were born at 39 weeks, compared to 40 weeks for non-exposed babies; 15 percent were born prematurely, compared to 6 percent of the control group; and average birthweight was a bit lower for the colchicine-exposed infants (6.6 pounds compared to 7.3 pounds).

All of these effects could be due to the illness being treated with colchicine, the drug itself, or both, Ornoy and colleagues say.

The current study, they conclude, "supports the safety of colchicine in pregnant women."