Fertility trends by HIV status in a health and demographic surveillance study in Magu District, Tanzania, 1994–2018

BACKGROUND: Sub-Saharan Africa (SSA) has the highest fertility rates and highest HIV disease burden globally. However, it is not clear how the rapid expansion of anti-retroviral therapy (ART) for HIV has impacted the fertility gap between HIV-infected and uninfected women. We used data from a Health and Demographic Surveillance System (HDSS) in north-western Tanzania to explore trends in fertility rates and the relationship between HIV and fertility over the 25-year period. METHODS: From 1994 to 2018, births and population denominators from the HDSS population were used to obtain age-specific fertility rates (ASFRs) and total fertility rates (TFRs). HIV status was extracted from eight rounds of epidemiologic serological surveillances (1994–2017). Fertility rates by HIV status and in different levels of ART availability were compared over time. Independent risk factors for fertility changes were examined using Cox proportional hazard models. RESULTS: There were 24,662 births from 36,814 women (15–49) who contributed a total of 145,452.5 Person-Years of follow-ups. The TFR declined from 6.5 births per woman in 1994–1998 to 4.3 births per woman in 2014–2018. The number of births per woman was 40% lower in women living with HIV than in HIV-uninfected women (4.4 vs. 6.7), although this difference narrowed over time. The fertility rate in HIV-uninfected women was 36% lower in 2013–2018 than in 1994–1998(age-adjusted HR = 0.641; 95% CI 0.613–0.673). In contrast, the fertility rate in women living with HIV was relatively unchanged over the same follow up period (age-adjusted HR = 1.099; 95% CI 0.870–1.387). CONCLUSIONS: There was a notable fertility decline among women in the study area from 1994 to 2018. Fertility remained lower in women living with HIV than in HIV-uninfected women, but the difference continued to narrow over time. These results highlight the need for more research into fertility changes, fertility desire and family planning use in Tanzanian rural communities.