assume gestation is 40 weeks, then subtract 24 weeks for viability, so ~16 weeks before birth

[roughly June 11, 2024, backtest and figure out if he dies between June 11 and June 30]

EDIT UPDATED DEFINITIONS

https://healthcare.utah.edu/womens-health/pregnancy-birth/preterm-birth/when-is-it-safe-to-deliver#:~:text=If%20a%20fetus%20reaches%2032,as%20high%20as%2095%20percent.

Resolves to 85 percent yes at July 9. 28 weeks is 80 percent viability

If Jimmy Carter dies between July and October, he becomes the first centenarian president BY OBJECTIVE DEFINITION, there's no denying it.

[viability centenarian might be the most important definition of centenarian - babies are older than their birthdate - preterm babies are not older than babies conceived earlier but born later]