Why Nigeria’s birth rate is falling (2018 to 2023 to 24), and what is driving the change

What is it about?

This paper examines Nigeria’s decline in total fertility rate (TFR) between the 2018 Nigeria Demographic and Health Survey (NDHS) and the 2023 to 24 NDHS. It does not just say “fertility went down.” Instead, it breaks the decline into the main demographic mechanisms that directly affect births, using the Bongaarts proximate determinants model. That model explains fertility using four direct factors: Marriage or sexual exposure (Cm) Contraception (Cc) Postpartum infecundability (Ci), mostly linked to breastfeeding and amenorrhea Abortion (Ca), treated as a residual since NDHS does not measure abortion well The study finds fertility declined from about 5.24 to 4.74 births per woman using microdata (very close to the official 5.3 to 4.8). It then decomposes the decline of about 0.505 births per woman into the percentage contribution of each proximate factor.

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Photo by Suhyeon Choi on Unsplash

Photo by Suhyeon Choi on Unsplash

Why is it important?

This work matters for a few big reasons. First, Nigeria is the largest population in Africa, so even a small fertility change has major consequences for schools, health systems, jobs, housing, and long term development. Second, this paper goes beyond describing trends and instead answers a policy relevant question: What is actually causing fertility to decline? That matters because different drivers imply different interventions. For example: If fertility is declining mostly due to contraception, then expanding access and method choice is central. If it is declining mostly due to delayed marriage or lower union formation, then social and educational shifts may be more important. If postpartum infecundability is a major driver, then breastfeeding patterns and child health dynamics are unexpectedly shaping fertility. Third, the results show Nigeria’s fertility decline is happening through multiple interacting pathways, not just one single change. That suggests Nigeria is in a gradual and uneven transition rather than a sudden demographic shift.this is a useful and credible demographic accounting study because it applies the well known Bongaarts proximate determinants framework to newly available NDHS microdata and clearly shows what is driving Nigeria’s fertility decline. The results are easy to interpret and suggest the decline from 2018 to 2023 to 24 is mostly explained by stronger fertility inhibition from postpartum infecundability (about 39 percent) and contraception (about 36 percent), with smaller contribution from reduced marriage or sexual exposure (about 21 percent) and a minimal residual. The most important caution is that the postpartum result is somewhat counterintuitive given expected urbanization effects, so subgroup checks would strengthen the interpretation, and like all decompositions, the findings should be treated as descriptive rather than fully causal.

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