Post-pregnancy damage
My weight and shape returned to pre-pregnancy within about 6 months, but my breasts got stretch marks and saggage, and I have had to worry about urine leaking during jumping jacks movements if I don't make sure I empty my bladder immediately before anything high impact. I only had one baby and it was 15 years ago. I have seen many cases where a woman's body rebounds from one baby but the second one ruins them. Maybe it's youth, maybe it's the sibling squabbling that gets them. I dunno.