여자는 태어날 때 생리 횟수가 정해짐 
근데 임신하는 순간 생리가 멈추게 됨 
애를 많이 낳을 수록 멈춘 생리 횟수는 늘어나고 
이게 폐경을 지연시킴 

그만큼 육체적으로 젊은 상태 유지 

나이 먹을 수록,
애 안 낳은 여자들이 애 3명 낳은 여자보다 
더 늙어보이는 이유가 거기 있음

 

I do not know if this answer applies so much to Eastern women versus Western ones BUT women who have more children often age less! Rabbi Adin Steinsaltz in one of his commentaries on the Talmud (Sanhedrin?) explains the notion thusly:

A woman has a predetermined number of menstrual periods before reaching menopause. Getting pregnant and nursing the baby after that means less menstrual periods during the time in question. This time is added on to the total. Her cycles continue for a longer time. Menopause comes later. The lady therefore stays younger in appearance and more physically amenable for more years than would otherwise be the case. This observation is based on the assumption that all other factors remain equal. A positive attitude, proper diet, exercise, family harmony, heredity, etc, also have their influence.