The effect of lactation on ovulation and fertility.

It has long been recognized that women who breastfeed their children have a longer period of amenorrhea and infertility following delivery than do those women who do not breastfeed. The length of postpartum amenorrhea is quite variable, and depends on several factors, including maternal age and parity, and the duration and frequency of breastfeeding. In general, it would appear that the more frequent and the longer the episodes of breastfeeding, the longer will be the period of anovulation, and the longer the period of infertility.