The populations of most less economically developed countries (LEDCs) are growing very rapidly. Most are at stage 2 and 3 of the Demographic Transition Model. They have declining deaths rates and high birth rates. Therefore, natural increase is high.
Death rates are declining because of improvements in sanitation and healthcare.
Birth rates are high for a number of reasons:
Lack of family planning education or contraceptives
In rural areas children are needed as labour on farms. In urban areas they are needed to work in the informal sector to earn money for their families.
Women have a large number of children as there is a high level of infant mortality
- Culture/religion mean it is unacceptable to use contraception