Maternal stress during pregnancy and early postnatal life has repeatedly been shown to have programming effects on later health. How these programming effects contribute to adult mortality remains largely unknown, due to a lack of available historical experiments with long follow-up of adult mortality. Thanks to unique French legislation established in 1917 for war orphans and children of disabled soldiers, the pupille de la Nation (orphan of the Nation) status, we were able to study the adult mortality of individuals born in 1914–1916 whose fathers were killed during World War 1. Vital information and socio-demographic characteristics were extracted manually from historical civil registers for 5,671 children born between 1 August 1914 and 31 December 1916 who were granted the status of pupille de la Nation. Linkage of civil registers with a nationwide database of 1.4 million soldiers who died during the War enabled us to identify war orphans among pupilles and collect information on their fathers. Each orphan was paired with a nonorphan from the same birth register matched for date of birth, sex and mother’s age at the infant’s birth. Mortality between ages 31 and 99 y was analyzed for 2,365 orphan/nonorphan pairs alive at age 31. The mean loss of adult lifespan of orphans who had lost their father before birth was 2.4 y (95% CI: 0.7, 3.9 y) and was the result of increased mortality before age 65 y. Adult lifespan was not reduced when the father’s death occurred after the infant’s birth. These results support the notion that intrauterine exposure to a major psychological maternal stress can affect human longevity. The lack of evidence for an association between postnatal loss of father and reduced adult longevity suggests efficient buffers existed to prevent programming by postnatal maternal stress.