Purpose

We assessed 18-month cumulative mother-to-child HIV transmission (MTCT) risk and risk factors for no antiretroviral medication use during pregnancy among adolescent, young women, and adult mothers in Zimbabwe.

Methods

We analyzed data from a prospective survey of 1,171 mother–infant pairs with HIV-exposed infants aged 4–12 weeks who were recruited from 151 immunization clinics from February to August 2013. HIV-exposed infants were followed until diagnosed with HIV, death, or age 18 months. Findings were weighted and adjusted for complex survey design and nonresponse.

Results

The 18-month cumulative MTCT risk was highest among adolescent aged ≤19 years (12%) followed by young women aged 20–24 years (7.5%) and adult women aged ≥25 years (6.9%). Across these groups, more than 94% had ≥1 antenatal care visit by 21 weeks of gestation, more than 95% had ≥1 HIV test, and more than 98% knew their HIV status. Of known HIV-positive mothers, maternal antiretroviral medication coverage during pregnancy was 76.8% (95% confidence interval: 65.1–85.5), 83.8% (78.6–87.9), and 87.8% (84.6–90.4) among adolescent, young women, and adult mothers, respectively. Among HIV-positive mothers diagnosed prenatally, the adjusted odds ratio of no ARV use during pregnancy was increased among those who had no antenatal care attendance (adjusted odds ratio: 7.7 [3.7–16.0]), no HIV testing (7.3 [2.3–23.5]), no prepartum CD4 count testing (2.1 [1.3–3.4]), and maternal HIV identification during pregnancy (2.9 [1.8–4.8]). Age was not a risk factor.

Conclusions

With similar coverage of prevention of MTCT services, the 18-month cumulative MTCT risk was higher among adolescents and young women, compared with adults. Additional research should examine the causes to develop targeted interventions.