Fertility history and post-reproductive survival: Villagrande (1830-2013)

We have analyzed the relationship between the fertility of mothers who survived age 50 (n=522) and their overall lifespan. We found that, adjusting for potential confounders (year of mothers’ birth, survival of spouse), delayed childbirth is associated with a reduced mortality risk (HR: 0.969), in particular, a 3-year delay in the average age at delivery is associated with a 10% reduction in mortality. These findings support the hypothesis that a delay in childbearing is favorable to a mother's survival. We also found that a higher proportion of male children decreases the mortality risk of the mother and that the survival of mothers whose average age at the birth of sons is > 35 is consistently better (p=0.005; log-rank test). Such results are in disagreement with other recent findings and we suggest further investigations of the impact of the socio-cultural characteristics.