The effects of family planning type and prevalent use on fertility and under-five mortality in Tanzania.

Current projections estimate that the population of Tanzania will triple by 2050, reaching 110 million. Voluntary family planning (FP) is the best strategy to curb population growth. However, contraception availability varies across regions. This study accounts for the regional context in which contraceptive choices -- and reproductive outcomes -- occur. Its research question, then, is: what is the effect of the regional context on total fertility rate and under-five mortality rate? This study employs the 2010 Tanzania Demographics and Health Survey (DHS), a representative probability sample of 10,139 women ages 15 to 49. To mimic randomization, regions are matched on education, wealth, and urban-rural status, and assumed to be exchangeable save for their exposure to an FP method. The region-level independent effect of a specific FP method on total fertility rate and under-five mortality rate is calculated for different types of FP methods (i.e., oral contraceptives, injectables, condoms, sterilization, traditional methods). Also, population projections are re-calculated for incremental prevalence of each method. Only permanent methods significantly reduce the total fertility rate, with an average causal effect of -1.59 children (-2.55, -0.65). Indeed, they alone guarantee the end of reproductive events. No method significantly reduces under-five mortality. Population growth trends would be most impacted by oral contraceptives (from 40 million in 2010 to 33 million in 2025 if prevalence increases by 19%), followed by injectables (42 million in 2025 with 19% prevalence increase). This difference is due to continued use of oral contraceptives through a woman's twenties and thirties, while injectables are mostly used by women in their twenties. These results suggest that sterilization immediately impacts on a region's total fertility rate. However, long-term investments in oral and injectable contraceptives will have a significant impact reducing population growth, and should be given funding priority.