Women in 38 out of the 54 African countries bear more than four children on average, the United Nations Population Fund (UNFPA) said on Wednesday.

The revelation came as the population agency published a report projecting that the world's population would grow by 2.2 billion by 2050, and more than half of that growth – 1.3 billion – is likely to be in sub-Saharan Africa.

According to UNFPA's projection, Africa's share of the world population will grow from 17 per cent in 2017, to 26 per cent in 2050.

The agency pointed that the population growth as projected for Africa is because women's rights are hampered by limited access to healthcare and education, along with “entrenched gender discrimination”.

The UNFPA Director in Geneva, Monica Ferro, said the trend globally is towards smaller families, indicating that more people are making choices about exactly how many children they want, or can afford to raise.

She however noted that despite the gradual transition to lower fertility rates, no country can claim that all their citizens enjoy reproductive rights at all times.

“No matter if it is a high fertility-rate country or low fertility-rate country, in both of them, you will find individuals and couples who say they don't have the number of children they want. They either have too many or too few,” she told journalists.

The report by the population agency also noted that the fertility rates in Africa are “significantly lower” in cities than in rural areas. In Ethiopia, for example, women have around 2.1 children in cities, whereas they have around five in the rest of the country.

Ferro urged all countries to implement a range of policies and programmes that would increase the “reproductive choices” of their populations.