A woman 26 years 6 months ago had delivery. A child on the breast nutrition. She came to doctor because of absence of menstruation, they did not appear after childbirth. When bimanual examination the uterus is not enlarged, firm, appendages are not defined. What is the most likely diagnosis?
1) Chiari - Frommelya Syndrome
2) Pregnancy 3 - 5 weeks
3) Crypto-amenorrhea
4) Lactational amenorrhea
5) Sheehan syndrome