I can still recall my professor who taught us about female ovulation. One thing she stressed out was the secretion of progesterone during pregnancy. It is a female hormone produced by ovaries that helps prepare the lining of uterus to get the egg if it becomes fertilized by sperm. It is difficlut to comprehend the process if you are not interested with it. Being a Biology major helped me to know more about the simpliest and deepest forms of life.