MONDAY, May 23 (HealthDay News) -- Two antibiotics that were linked to birth defects may be safe to take during pregnancy after all, an obsetricians/gynecologists group says.

The antibiotics, nitrofurans and sulfonamides, are typically used to treat urinary tract infections, at least until a 2009 report found that the antibiotics may increase the risk for birth defects if taken during the first trimester of pregnancy.

But after reviewing the existing research, the American College of Obstetricians and Gynecologists (ACOG) determined that the antibiotics are still "appropriate when there is no suitable alternative," according to an ACOG news release.

The 2009 study that raised alarm about the antibiotics had significant limitations, including that it relied on women's recall of what they'd taken during pregnancy. In addition, subsequent studies found no link between nitrofurans and sulfonamides and birth defects.

"Antibiotics are commonly prescribed during pregnancy for a variety of bacterial infections, so there is considerable data now on the relationship of antibiotic exposure to birth defects," said Dr. William H. Barth, Jr., chair of ACOG's Committee on Obstetric Practice, in a news release.

The 2009 study "had several significant limitations, including patient recall bias. Furthermore, this was an observational study, so it's impossible to know whether the birth defects were caused by the antibiotic or the infection itself, or some other factor," he added.

ACOG's Committee Opinion was published in the June issue of Obstetrics & Gynecology.

More information

The National Women's Health Information Center provides detailed information on medication use during pregnancy.