The chance of conception during lactation.

Many mothers in low-income countries, particularly in rural areas, nurse their children for 1–2 years on the average. The main purpose of this practice is, of course, to provide the newborn child with the nutrition necessary for its survival. Prolonged breast-feeding, however, also has a birth-spacing effect and postpones the next pregnancy by inhibiting ovulation and by delaying resumption of the menstrual cycle. Suckling of the infant is important for this suppression of the menstrual cycle because it leads to the release of prolactin, which not only plays an important role in milk production but also inhibits the release of gonadotrophins which initiate resumption of the menstrual cycle. For further details about these endocrinological aspects of lactation see, for example, Rolland et al. (1975); Thomson, Hytten & Black (1975) and Buchanan (1975). [ABSTRACT FROM AUTHOR]