Variations in Natural Fertility: The Effect of Lactation and Other Determinants

The analysis focuses on average waiting times to a fertile conception, as derived from non-contraceptive exposure in second and higher-order birth intervals. Life-table estimates are derived from exposure in the two-year periods preceding the survey, for 20 surveys in Africa, Asia and Latin America undertaken as part of the WFS programme. Differences in the waiting time to conception are examined as a function of the duration of lactation and post partum abstinence. In addition, the extent to which variations in waiting times are produced by country and regional effects, and effects due to age, duration of marriage and parity are examined. The analysis points out the dangers of deriving estimates of natural fertility from the sub-group of women who never breastfed.