Birth rate
The region of Sub-Saharan Africa has the highest birth rate in the world. As of 2016, Niger, Mali, Uganda, Zambia, and Burundi have the highest birth rates in the world. This is part of the fertility-income paradox, as these countries are very poor, and it may seem counter-intuitive for families there to have so many children. The inverse relationship between income and fertility has been termed a "demographic-economic "paradox"" by the notion that greater means would enable the production of more offspring as suggested by the influential Thomas Malthus.
Prevalence of teenage pregnancy
The highest rate of teenage pregnancy in the world — 143 per 1,000 girls aged 15–19 years — is in sub-Saharan Africa. Women in Africa, in general, get married at much earlier ages than women elsewhere — leading to earlier pregnancies. In Nigeria, according to the Health and Demographic Survey in 1992, 47% of women aged 20–24 were married before 15 and 87% before 18. 53% of those surveyed also had given birth to a child before the age of 18. Teenage birth rates in African countries (2002) According to data from World Bank, as of 2015, the highest incidence of births among 15-19 years old girls was in: Niger, Mali, Angola, Guinea and Mozambique.