One central rationale for the promotion of family planning is the potential benefit to the health of mothers and children. The achievement of adequate spacing between pregnancies is a major pathway through which contraceptive practice can render benefits. Pregnancies conceived less than 20 months following a prior birth are at considerably higher risk of prematurity, low birth weight, fetal death and early neonatal death. 1 The importance of this link is underscored by the facts that neonatal deaths account for 44% of all childhood deaths and that prematurity is the most common cause. 2 In addition to the 2.9 million neonatal deaths that occur each year, 99% in low-and middleincome countries, an almost equal number of stillbirths occur. 3 An analysis of Demographic and Health Survey (DHS) data from 52 countries showed that the adverse effects of inadequate spacing extend beyond the neonatal period. 4 Expressed in terms of interbirth intervals, children born within 24 months of an elder sibling have a 60% increased risk of dying before their first birthday and those born 2-3 years after an elder sibling have a 10% increased risk, compared with those born after an interval of 3-5 years. For children between the ages of one and five years, the balance of evidence suggests that intervals of less than two years are associated with a 40% increased risk of dying. A systematic review confirmed that the health of mothers is also affected by inadequate spacing. 5 Specifically, short intervals are associated with uterine rupture and uteroplacental bleeding disorders. Despite the steep rise in contraceptive use in developing countries, interbirth intervals have increased in length only slightly over the past 25 years; according to recent surveys, 25% of second and higher-order children are born within two years of a sibling, compared with about 29% a decade earlier.
6Though this evidence underlines the importance of postpartum family planning for the health of both mothers and children, the topic suffered a prolonged era of benign neglect that has only recently been remedied. In 2013, the World Health Organization issued new guidelines for this component of contraceptive services and the U.S. Agency for International Development is funding projects to provide postpartum services. 7,8 One factor that helped to revitalize this agenda was a study of women in 27 countries by Ross and Winfrey in which the proportion who wanted to postpone another child for at least two years but were using no method of contraception was, on average, at the very high level of 65% in the first year following childbirth. 9 Indeed, their analysis suggested that 39% of all unmet need for contraception arose from women who had given birth in the previous 12 months. For decades, the concept of unmet need has been the main way of prioritizing populations for delivery of family planning services, and thus Ross and Winfrey's article had a major impact. However, their findings are perplexing because it is well established that most couples wish to space su...