Modeling Contraception and Pregnancy in Malawi: A Thanzi La Onse Mathematical Modeling Study

Abstract

Malawi has high unmet need for contraception with a costed national plan to increase contraception use. Estimating how such investments might impact future population size in Malawi can help policymakers understand effects and value of policies to increase contraception uptake. We developed a new model of contraception and pregnancy using individual-level data capturing complexities of contraception initiation, switching, discontinuation, and failure by contraception method, accounting for differences by individual characteristics. We modeled contraception scale-up via a population campaign to increase initiation of contraception (Pop) and a postpartum family planning intervention (PPFP). We calibrated the model without new interventions to the UN World Population Prospects 2019 medium variant projection of births for Malawi. Without interventions Malawi's population passes 60 million in 2084; with Pop and PPFP interventions. it peaks below 35 million by 2100. We compare contraception coverage and costs, by method, with and without interventions, from 2023 to 2050. We estimate investments in contraception scale-up correspond to only 0.9 percent of total health expenditure per capita though could result in dramatic reductions of current pressures of very rapid population growth on health services, schools, land, and society, helping Malawi achieve national and global health and development goals.

FIGURE 1

Conceptual overview of the model of contraception and pregnancy

FIGURE 2

Model births and population results: (a) number of births, (b) population pyramid in 2018, (c) population pyramid in 2050, and (d) population size. (Left) Calibration (without Pop and PPFP interventions). (Right) Effect of Pop and PPFP interventions starting 2023. The dotted vertical line shows the start of the interventions, year 2023

FIGURE 3

Model results without and with Pop and PPFP interventions: (a) proportion of females 15–49 years old using a contraceptive, (b) mean proportion of females 15–49 years old becoming pregnant per year, (c) proportions of females 15–49 years old using contraception methods, and (d) dependency ratio: number of dependents (children aged 0–14 and adults aged over 65) per adult aged 15–64. (Left) without Pop and PPFP interventions. (Right) with Pop and PPFP interventions since 2023. The dotted vertical line shows the start of the interventions, year 2023

FIGURE 4

Contraception consumables and intervention costs with and without interventions 2023–2050