What are estrogen and progesterone?

Hormones.: Estrogen and Progesterone are hormones produced by the ovary in response to the brain (pituitary gland). Estrogen is produced early in a womans cycle and Progesterone in the second half of the menstrual cycle. The are responsible for preparing the uterus for pregnancy and for pregnancy maintenance. They are also responsible for making women, women.

Inner lining: Estrogens produced by the ovaries during the first half of the menstrual cycle, before ovulation, make the inner lining of the uterus grow to provide a nice cushion for a fertilized egg. After ovulation the ovaries start producing progesterone which transforms the inner lining into that nice cushion. When there is no pregnancy, both hormone levels drop at the end of the cycle and menses commence.