Breast-feeding as a Method of Birth Control

Because breast-feeding delays the onset of menstruation after pregnancy, a phenomenon that is easily observed, it has often been regarded as a form of birth control. It is, however, only a relatively short-term one. Modern studies in developing countries show that mothers who breastfeed for an extended period do not begin menstruating until an average of ten months after delivery as compared with three months for mothers who do not breast-feed for a long period. It also takes breast-feeding mothers longer to conceive a child after their most recent birth event, perhaps because fertility is not at its height. This sterility is based on the assumption that the infant has little solid food and is entirely dependent on breast-feeding. If solid foods are offered, the window of nonfertility is lessened. Some practices associated with breast-feeding, however, might have lengthened this window. Many peoples including the Greeks and the Romans held that sexual intercourse spoiled the milk and, because some of these same cultures believed that children should be nursed at least for three years, long periods of abstinence would have been associated with breast-feeding. Other factors are involved as well. The onset of menstruation, even with lactating women, is closely associated with levels of nutrition and physical well-being. A comparative study of Bostonian and Taiwanese women who breast-feed indicated that a higher percentage of Boston women had begun to menstruate within six months of weaning than had Taiwanese women. The best advice today for women who are breast-feeding and who are also engaging in sexual intercourse is to use one of the methods of contraception available as well.