I think it's unlikely given the length of time people actually lived before civilization. More likely there's just no evolutionary advantage in female fertilit

I think it's unlikely given the length of time people actually lived before civilization. More likely there's just no evolutionary advantage in female fertility after age 40 - she starts having children at 14 or 15 and has one a year until she dies in childbirth. She never makes it to middle age. Why accept there's no advantage in other age-related breakdown (like arthritis or failing eyesight) and expect there's some grand evolutionary plan in fertility loss?