Normal Progesterone Estrogen Cycle.

Cycle Estrogen Progesterone Related Events
Day 1, Menstruation
Low
Low ( A few mg. per day)
 If pregnancy does not take place, the uterine lining is shed (menstruation), and another monthly cycle starts.
Day 3
Low
Low
GnRH from hypothalamus stimulates the pituitary to send follicle stimulating hormone to the ovary, initiating follicle (egg sack) maturation and thickening of uterine lining.
Day 10
Surge to high
Low
Mature follicle releases estrogen to promote thickening of uterine lining and to stimulate the pituitary gland's secretion of luteinizing hormone that induces ovulation.
Day 14, Ovulation
Medium
Starts to rise up to 30 mg/day
 If ovulation fails, Progesterone is not produced.
Day 24
Drops to low level
Drops to low level
 If the egg is fertilized, progesterone from ovary continues to rise. Any drop in progesterone level results in menstruation or miscarriage. Later during pregnancy, the placenta produces up to 3000 to 4000 mg/day of progesterone .
Day 1, menstruation
Low
Low
 The drop in estrogen and progesterone level triggers menstruation as well as GnRH secretion in hypothalamus.
After menopause
estradiol: 15% of premenopausal level
estrone: 40 to 50% of premenopausal level
Low
 Estrogen still produced in fat, muscle and skin cells by converting androstenedione produced in the ovary and adrenals. Low level of progesterone still produced by adrenals and brain.