As part of Disease Control Priorities 3rd Edition, the World Bank will publish a volume on Reproductive, Maternal, Newborn, and Child Health that identifies essential cost-effective health interventions that can be scaled up to reduce maternal, newborn, and child deaths, and stillbirths. This Review summarises the volume's key findings and estimates the effect and cost of expanded implementation of these interventions. Recognising that a continuum of care from the adolescent girl, woman, or mother to child is needed, the volume includes details of preventive and therapeutic health interventions in integrated packages: Maternal and Newborn Health and Child Health (along with folic acid supplementation, a key reproductive health intervention). Scaling up all interventions in these packages from coverage in 2015 to hypothetically immediately achieve 90% coverage would avert 149 000 maternal deaths, 849 000 stillbirths, 1 498 000 neonatal deaths, and 1 515 000 additional child deaths. In alternative calculations that consider only the effects of reducing the number of pregnancies by provision of contraceptive services as part of a Reproductive Health package, meeting 90% of the unmet need for contraception would reduce global births by almost 28 million and consequently avert deaths that could have occurred at 2015 rates of fertility and mortality. Thus, 67 000 maternal deaths, 440 000 neonatal deaths, 473 000 child deaths, and 564 000 stillbirths could be averted from avoided pregnancies. Particularly effective interventions in the Maternal and Newborn Health and Child Health packages would be management of labour and delivery, care of preterm births, and treatment of serious infectious diseases and acute malnutrition. Nearly all of these essential interventions can be delivered by health workers in the community or in primary health centres, which can increase population access to needed services. The annual incremental cost of immediately scaling up these essential interventions would be US$6·2 billion in low-income countries, $12·4 billion in lower-middle-income countries, and $8·0 billion in upper-middle-income countries. With the additional funding, greater focus on high-effect integrated interventions and innovations in service delivery, such as task shifting to other groups of health workers and supply and demand incentives, can help rectify major gaps in accessibility and quality of care. In recent decades, reduction of avoidable maternal and child deaths has been a global priority. With continued priority and expansion of essential reproductive, maternal, newborn, and child health interventions to high coverage, equity, and quality, as well as interventions to address underlying problems such as women's low status in society and violence against women, these deaths and substantial morbidity can be largely eliminated in another generation.