The only significant difference involved a bowel condition, necrotizing enterocolitis, often associated with prematurity. Two premature babies in the treatment group were born with this condition. Each of the mothers, however, received a different anti-flu drug, so the prematurity may have been the major common factor, said Dr. Laura Greer, assistant instructor of obstetrics and gynecology and lead author of the paper.

One limitation of study was that only 13 percent of the women with flu were treated during the first trimester, a critical time in fetal development. "Overall, this study provides important safety data to guide clinicians and patients in treating influenza in pregnancy," Dr. Greer said.

The data collection stopped a year before the pandemic H1N1 flu strain, or swine flu, became widespread. Tamiflu was used in 2009 to treat pandemic H1N1 infection, a type of influenza A; it is also effective in treating seasonal influenza A and B infection. The other two medications were more commonly used in earlier influenza seasons.

SOURCE UT Southwestern Medical Center