Their findings suggested that "the complex set of immunologic changes" that occur during pregnancy may be interacting as a benefactor with the combination drug therapy.
"After using statistical modelling methods to adjust for differences between women, including their age, health and response to therapy, the researchers found that 'pregnant women did better,'" said Timothy Sterling, M.D., the study's senior author and associate professor of Medicine.
In the developing world, previous studies, had reported higher levels of complications and deaths among pregnant women who suffered AIDS.
But those studies were conducted before the initiation of highly active anti-retroviral therapy (HAART), drug "cocktails" that have over the past decade dramatically reduced death and complication rates among people infected with the AIDS-causing human immunodeficiency virus (HIV).
The study included 759 women, which were treated between 1997 and 2004 at Nashville's Comprehensive Care Center. Above 500 of these women received HAART, including 119 of the 139 women who had at least one pregnancy during the study period.
Also the women who became pregnant more than once during the study inclined towards a lower risk of disease progression than the ones who became pregnant only once.
Sterling cautioned that pregnant women were healthier than the women who didn't became pregnant, and they may have been more likely to adhere to their therapy out of concern for the foetus.
"Intensive care" was given to them consisting of frequent visits with their physician, case managers and nutritional counsellors.
"Perhaps efforts should be made to do that for everyone, pregnant or not, female or male," he said.
The study was posted on the online edition of the Journal of Infectious Diseases.