Gestation period, oocytes, vaginal pH, menstrual cycle: normal numbers Mnemonic

4 is the normal pH of the vagina.
40 weeks is the normal gestation period.
400 oocytes released between menarche and menopause.
400,000 oocytes present at puberty.
28 days in a normal menstrual cycle.
280 days (from last normal menstrual period) in a normal gestation period.