For example, in a normal perimenopausal woman, it’s not unusual for her FSH level to be low one day and then quite high the next. Estradiol levels. Estradiol is the main form of estrogen found in premenopausal women. A normal level is 30-400 picograms per millileter (pg/mL), but after menopause, it falls below 30 pg/mL.