Women living with HIV who begin antiretroviral (ARV) treatment prior to conceiving a child, compared with those who begin ARVs afterward, have a higher risk of giving birth to a baby who is small for gestational age (SGA), aidsmap reports. Nevertheless, the benefits of HIV treatment to both expectant mothers and their unborn babies—ARVs prevent mother-to-child-transmission of the virus—far outweigh such risks.

Publishing their findings in PLOS ONE, researchers in the Netherlands conducted a retrospective study of 1,022 HIV-positive women who gave birth between 1997 and 2015. They compared these women’s birth outcomes with those of a group of HIV-negative women of sub-Saharan African origin who lived in Rotterdam.

Newborns are considered SGA if they are below the 10th percentile for weight based on how far along their mothers were in their pregnancy when they gave birth. As the study authors point out, “Fetal growth restriction, resulting in SGA, is a serious condition with increased [sickness and death], including neurodevelopment delay, as well as [high blood pressure], obesity and [diabetes] in adulthood.”

The investigators’ analysis focused on 1,392 non-twin births among the HIV-positive women. A total of 550 of the mothers of these babies started ARVs prior to conception.

About 24 percent of the HIV-positive mothers’ babies were SGA, compared with 1.4 percent of the HIV-negative comparison group. Among the HIV-positive women, the rate of babies who were born SGA was 27 percent among those who started ARVs before conception and 22 percent among those who started after. This difference was statistically significant, meaning that it was unlikely to have been driven by chance.

After adjusting the data for various factors, the researchers found that starting ARVs before conception, compared with starting afterward, was associated with a 35 percent increased risk of a baby being born SGA.

When the study authors parsed their data according to the ARV drug class the women took, they found that there was only a statistically significant difference in SGA risk among those who took protease inhibitors. Women who took this class of drug prior to conception had a 49 percent increased risk of giving birth to an SGA baby compared with women who started protease inhibitors after conception.

More research is needed to analyze the association of various classes of ARV drugs and birth outcomes and to determine the preferred regimens for individual HIV-positive women of childbearing age.

The HIV-positive women’s newborns were a median 0.73 pounds lighter than the HIV-negative women’s.

To read the aidsmap article, click here.

To read the study, click here.