Antiretroviral Therapy during Pregnancy Significantly Reduces Mother-to-child HIV Transmission, but is Linked to Low Birth Weight

By Liz Highleyman

Since the mid-1990s, it has been known that prophylactic use of certain antiretroviral drugs during pregnancy -- namely zidovudine (AZT; Retrovir) and nevirapine (Viramune) -- dramatically reduces the risk of mother-to-child HIV transmission. However, outcomes in women who use triple combination antiretroviral therapy during pregnancy are less well characterized.

In a report published in the September 12, 2008 issue of AIDS, researchers with the French/African Ditrame Plus and MTCT-Plus Projects studied pregnancy outcomes in 326 HIV-1-infected pregnant women receiving antiretroviral therapy in Abidjan, Cote d'Ivoire.

Between March 2001 and July 2003, HAART was not yet available, and women who would have been eligible for combination therapy based on their own disease status instead received a short-course of zidovudine (with or without lamivudine) plus a single dose of nevirapine during labor to prevent mother-to-child transmission (PMTCT group; n = 175). Between August 2003 and August 2007, women eligible for HAART received combination therapy (HAART group; n = 151). All infants received zidovudine and nevirapine after birth, and women were advised to either feed formula or exclusively breast-feed (shown to be safer than mixed feeding of breast milk plus other foods). Median CD4 cell counts were similar in the 2 groups (177 vs 182 cells/mm3, respectively).

The researchers recorded the frequencies of low birth weight (<2500 g), very low birth weight (below 2000 g), stillbirth, and infant mortality within the first year. Risk factors associated with low birth weight were investigated using a logistic regression model.

Results

• At 12 months, 3 infants (2.3%) became infected with HIV in the HAART group compared with 25 infants (16.1%) in the PMTCT group (P < 0.001).

• The rate of very low birth weight was similar in the 2 groups.

• The rate of low birth weight was nearly twice as high in HAART group compared with the PMTCT group (22.3% vs 12.4%; P = 0.02).

• In a multivariable analysis, after adjusting for maternal CD4 count, WHO disease stage, age, and body mass index (BMI), the following factors were significantly associated with low birth weight:

• HAART initiated before pregnancy (adjusted odds ratio [AOR] 2.88);

• HAART started during pregnancy (AOR 2.12);

• Low maternal BMI at the time of delivery (AOR 2.43).

• The rate of stillbirth was similar in both groups, at about 3%.

• The overall infant mortality rate during the first year was about 7%.

• Low birth weight and HAART use were not associated with a greater risk of infant death, though being HIV infected led to greater mortality.

Based on these findings, the study authors concluded that "HAART in pregnant African women with advanced HIV disease substantially reduced mother-to-child transmission, but was associated with low birth weight."

HIV transmission is less likely to occur when viral load is fully suppressed, and mothers are more likely to achieve undetectable viral load with combination HAART than with only zidovudine/nevirapine.

Given the highly significant reduction in the rate of HIV infection in babies born to women on HAART, and given that low birth weight infants were not more likely to die, this study indicates that the benefits of HAART for pregnant women outweigh the risks.

9/23/08

Reference
DK Ekouevi, PA Coffie, R Becquet, and others. Antiretroviral therapy in pregnant women with advanced HIV disease and pregnancy outcomes in Abidjan, Côte d'Ivoire. AIDS 22(14): 1815-1820. September 12, 2008.
(Abstract).