An absence of menstruation (amenorrhea) in reproductive age women is
usually due to an absence of ovulation (anovulation). If this becomes
prolonged, then these women are at risk for the ill effects associated
from chronically low estrogen levels (hypoestrogenemia).  
Specifically, the women at risk for this would be those experiencing
premature ovarian failure (early menopause) or hypothalamic
amenorrhea. Whatever the cause, hypoestrogenemia will eventually lead
to a shrinkin…