The Natural increase rate (NIR) can decline for only two reasons.

The first is lower birth rates.

The second reason is higher death rates.

The crude birth rate (CBR) had declined rapidly since 1990from twenty seven to twenty one in the world as a whole, from fifteen to ten in MDCs, and from thirty one to twenty four in LDCs.

One approach to lowering birth rates emphasizes the importance of improving local economic conditions.

A wealthier community has more money to spend on education and health-care programs that would promote lower birth rates. With improved health-care programs, IMRs would decline through such programs as improved prenatal care, counseling about sexually transmitted diseases, and child immunization. The survival of more infants ensured, woman would be more likely to choose to make more effective use of contraceptives to limit the number of children.

The other approach to lowering birth rates emphasizes the importance of rapidly diffusing modern contraceptives methods. Putting resources into family-planning programs can reduce birth rates much more rapidly. Rapid growth in the acceptance of family planning is evidence that in the modern world, ideas can diffuse rapidly, even to places where people have limited access to education and modern communications. Similar growth in the use of contraceptives has occurred in other LDCs, including Colombia, Morocco, and Thailand.

The percentage of woman using contraceptives is especially low in Africa, the reason for this is partly economics, religion, and education. Very high birth rates in Africa and southwestern Asia also reflect the relatively low statues of woman. In societies where woman receive less formal education and hold fewer legal rights than do men, women regard having a large number of children as a measure of their high status, and men regard it as a sign of their own virility.

Regardless of which alternative is more successful, many oppose birth-control programs for religious and political reasons. Opposition is strong within the United States to terminating pregnancy by abortion, and the U.S government has at times withheld aid to countries and family-planning organizations that advise abortion, even when such advice is only a small part of the overall aid program. LDCs governments and international family-planning organizations have limited funds to promote lower birth rates, so they must set priorities and make choices for allocating scarce funds.