Prolonged breastfeeding as a birth spacing method.

The majority of mothers in developing countries start nursing their babies after birth and continue for one to two years.1 One reason that nursing in developing countries is common and prolonged is the widespread belief that it is effective in postponing the next conception (Association Algerienne, 1971; Jelliffe, 1967; Marzouk, 1972; Niehoff and Meister, 1972; Wyon and Gordon, 1971; and Yaukey, 1961). This paper summarizes findings of recent investigations on the fertility reducing effect of breastfeeding. These studies fall into two groups: those that determine the effect of lactation on pregnancy and birth intervals; and those that focus on the impact of lactation on the resumption of ovulation and menstruation.