Association between number of children and mortality of mothers: results of a 37-year follow-up study

Abstract

Purpose To examine the association between parity and long term all-cause mortality and mortality due to specific causes in women. Methods This prospective population-based study included 40,454 mothers who gave birth in Western Jerusalem, Israel, to 125,842 children and were followed for an average of 37 years following the birth of their first child. Cox Proportional Hazards Models were used to evaluate long-term total and specific cause mortality of women by their parity. Results We found a U-shaped relationship between the number of offspring and risk of all-cause mortality in mothers. After adjustment for sociodemographic characteristics and maternal health and obstetric conditions, higher mortality rates were observed for mothers of 1 child (HR=1.18; 95% CI 1.04–1.4), mothers of 5–9 children (HR=1.21;95%CI 1.09–1.33), and mothers of ≥10 children (HR=1.49;95%CI 1.12–1.99) as compared to mothers of 2–4 children. Mortality risk from specific causes including coronary disease, circulatory disease, and cancer were increased for multiparous women. Conclusions In this long-term follow-up study, there was an association between number of children mortality risk of mothers. These findings suggest that maternal pregnancies and post-natal characteristics as reflected by number of children may have consequences for long-term maternal health.

Early-life stress and reproductive cost: A two-hit developmental model of accelerated aging?

“…First, although high parity in humans is the primary metric to test trade-offs between reproduction and longevity, there is a mixed evidence as to the effects of women bearing 2-4 children, suggesting perhaps a U-shaped relationship with significant effect for high parity, compared with 1 child or P5 children [112]. Second, as is evident in both nonhuman and human data, the effect of reproduction on aging processes may be especially evident at a young age [63,70,[113][114][115]; thus age at first reproduction may be a critical factor in evaluating the two-hit model of increased senescence and reduced longevity.…”

Influence of late-age births on maternal longevity

“…Parity was evaluated as a continuous and categorical variable. The categorical variable was classified as zero, one, two to five, or six or more children on the basis of the findings from previous studies in this and other populations [12,16,18]. An indicator variable for the year of last birth before 1988 was used to identify women who completed their reproductive history before the introduction of oocyte donation in Israel.…”

“…In addition to the comprehensive examination of the creation of the linked file, this previous study included an evaluation of the small proportion of individuals with missing ID on the census records. The numerous verification methods were used to link this and other ICBS study cohorts [17,18,20].…”

Current versus future reproduction and longevity: a re-evaluation of predictions and mechanisms

“…The queens of both bees and ants display very high fecundity and longevity that exceeds that of sterile workers (De Loof, 2011). Greater parity is associated with lower risk of mortality in recent populations of Norwegian (Grundy and Kravdal, 2008), but not Israeli, women (Dior et al, 2013). Thus we believe that it is both important to recognize the potential for positive effects to occur and to consider the bioenergetic mechanisms that are likely to support their occurrence.…”