A new study shows that the use of HIV drug during pregnancy to prevent mother-to-child transmission of HIV may have small but significant effect on the unborn baby's development, Tech Times reports.

The new study was published in the journal AIDS.

The researchers from Harvard University have found that the antiretroviral drug atazanavir could affect fetal development when taken by HIV-infected mothers during pregnancy.

The findings showed that the developmental effects on the children occur even if the child is born without acquiring HIV infection.

For the study, the researchers studied 167 women who received atazanavir during pregnancy and 750 who did not. The researchers compared the effect of the drug on the women's babies once their children turned 1 year old.

The results showed that the babies who were born to mothers who had antiretroviral drug had lower language and social-emotional development scores compared to children who were not exposed to the drug during fetal development.

"In utero exposure to atazanavir-containing regimens compared to non-atazanavir-containing regimens may adversely affect language and social-emotional development in PHEU infants during the first year of life, but the absolute difference is small," wrote Ellen Caniglia, from Harvard T.J. Chan School of Public Health, and colleagues in their study.

The study also found that the effect on social-emotional development was only found in children whose mothers started taking the drug during the second to third trimester of pregnancy but language development of the infants were affected regardless of the trimester in which the mothers took the drugs.