Higher fertility has a significantly negative effect on longevity for both women and men. That’s from an article Examining the trade-offs between human fertility and longevity over three centuries using crowdsourced genealogy data published in PLOS One earlier in the month.
It’s based on a sample of 81,924 women and 103,642 men born between 1601 and 1910 across 16 European countries. The negative effects are stronger among the older cohorts and have reduced over time.