Incidence of and outcomes of pregnancy in adolescents with perinatally-acquired HIV infection in Southern Africa

Background: The scale-up of antiretroviral therapy (ART) has enabled more children living with HIV to reach adolescence and become sexually active. We investigated pregnancy incidence and outcomes among adolescents with perinatally acquired HIV enrolled in a multi-country trial of vitamin D and calcium carbonate supplementation (VITALITY; PACTR202009897660297).

Methods: Between February and November 2021, 842 adolescents aged 11–19 years from Zambia and Zimbabwe on ART for at least 6 months were enrolled. Pregnancies occurring during 96 weeks of follow-up (February 2021–October 2023) were identified through self-report or testing. Pregnancy incidence rate was calculated among post-menarche participants using survival time analysis.

Results: Thirty-five adolescents (median age 18, range 13–22) became pregnant, 21 in Zambia, 14 in Zimbabwe. Overall pregnancy incidence was 4.6 per 100 person-years (95% CI 3.3–6.4), higher in those ≥15 years (6.8 per 100 person-years, 95% CI 4.8–9.7). Three pregnancies ended in miscarriage; 32 resulted in live births. Of the 30 adolescents with live births and available data, 26 (86.7%) infants were tested for HIV at birth: 24 were HIV-negative, two had unknown results. Twenty-nine received HIV prophylaxis. At 6 weeks, 19/30 infants were retested for HIV: 16 were HIV-negative. Twenty-one of 32 pregnant adolescents were in school at conception, and 4 (19.0%) returned post-pregnancy. Overall, 23/33 (69.7%) started contraception, a median of 9 weeks after delivery/miscarriage.

Conclusion: Pregnancy incidence is high among adolescents with HIV, especially older adolescents. While prevention of vertical HIV transmission is effective, education re-integration and timely contraception uptake remain limited.