What are some of the socio-economic causes of high population growth in sub-Saharan Africa?

Due to relative poverty in large parts of sub-Saharan Africa (especially in rural areas) a lot of people can't afford contraceptives even when they are available, furthermore, high rates of subsistence farming in this region make having multiple children valuable as they can work. Due to high infant mortality rates in sub-Saharan countries, people are also more inclined to have more children as more of them may die before adulthood. On top of this, a lack of social welfare in most sub-Saharan countries makes people want to have more children to take care of them when they're old. Finally, religious leaders who are influential may condem the use contraceptives.