Increasing contraceptive use in developing countries has cut the number of maternal deaths by 40% over the past 20 years, merely by reducing the number of unintended pregnancies. By preventing high-risk pregnancies, especially in women of high parities, and those that would have ended in unsafe abortion, increased contraceptive use has reduced the maternal mortality ratio—the risk of maternal death per 100 000 live births—by about 26% in little more than a decade. A further 30% of maternal deaths could be avoided by fulfilment of unmet need for contraception. The benefits of modern contraceptives to women’s health, including non-contraceptive benefits of specific methods, outweigh the risks. Contraception can also improve perinatal outcomes and child survival, mainly by lengthening interpregnancy intervals. In developing countries, the risk of prematurity and low birth weight doubles when conception occurs within 6 months of a previous birth, and children born within 2 years of an elder sibling are 60% more likely to die in infancy than are those born more than 2 years after their sibling.