Incidence and predictors of pregnancy among a cohort of HIV-positive women initiating antiretroviral therapy in Mbarara, Uganda

Abstract

Objective: Many people living with HIV in sub-Saharan Africa desire biological children. Implementation of HIV prevention strategies that support the reproductive goals of people living with HIV while minimizing HIV transmission risk to sexual partners and future children requires a comprehensive understanding of pregnancy in this population. We analyzed prospective cohort data to determine pregnancy incidence and predictors among HIV-positive women initiating antiretroviral therapy (ART) in a setting with high HIV prevalence and fertility.

Methods: Participants were enrolled in the Uganda AIDS Rural Treatment Outcomes (UARTO) cohort of HIV-positive individuals initiating ART in Mbarara. Bloodwork (including CD4 cells/mm(3), HIV viral load) and questionnaires (including socio-demographics, health status, sexual behavior, partner dynamics, HIV history, and self-reported pregnancy) were completed at baseline and quarterly. Our analysis includes 351 HIV-positive women (18-49 years) who enrolled between 2005-2011. We measured pregnancy incidence by proximal and distal time relative to ART initiation and used multivariable Cox proportional hazards regression analysis (with repeated events) to identify baseline and time-dependent predictors of pregnancy post-ART initiation.

Results: At baseline (pre-ART initiation), median age was 33 years [IQR: 27-37] and median prior livebirths was four [IQR: 2-6]. 38% were married with 61% reporting HIV-positive spouses. 73% of women had disclosed HIV status to a primary sexual partner. Median baseline CD4 was 137 cells/mm(3) [IQR: 81-207]. At enrolment, 9.1% (31/342) reported current pregnancy. After ART initiation, 84 women experienced 105 pregnancies over 3.8 median years of follow-up, yielding a pregnancy incidence of 9.40 per 100 WYs. Three years post-ART initiation, cumulative probability of at least one pregnancy was 28% and independently associated with younger age (Adjusted Hazard Ratio (AHR): 0.89/year increase; 95%CI: 0.86-0.92) and HIV serostatus disclosure to primary sexual partner (AHR: 2.45; 95%CI: 1.29-4.63).

Conclusions: Nearly one-third of women became pregnant within three years of initiating ART, highlighting the need for integrated services to prevent unintended pregnancies and reduce periconception-related risks for HIV-infected women choosing to conceive. Association with younger age and disclosure suggests a role for early and couples-based safer conception counselling.

Figure 1. Incidence of overall and first pregnancy.

Incidence of overall and first pregnancy (per 100 woman-years) by 6-month intervals post ART initiation (in months) (n = 314).

Figure 2. (a–d). Kaplan-Meier curves of probability of pregnancy.

Kaplan-Meier curves of probability of pregnancy over time (n = 314). Figure 2a. Overall. Figure 2b. Stratified by age. Figure 2c. Stratified by marital status. Figure 2d. Stratified by disclosure. Figure 2a. Probability of pregnancy over time among HIV-positive women initiating ART. Figure 2b. Probability of pregnancy over time among HIV-positive women initiating ART, stratified by age (<35 years vs. > = 35 years). Figure 2c. Probability of pregnancy over time among HIV-positive women initiating ART, stratified by marital status (Currently married vs. not currently married). Figure 2d. Probability of pregnancy over time among HIV-positive women initiating ART, stratified by disclosure of HIV status to primary partner (Non-disclosure vs. Disclosure vs. No primary partner (N/A)).