Progesterone is responsible for three things. If pregnancy does not take place the uterine lining - endometrium is shed which causes the cyclical bleeding from the uterus to occur which we all know as menstruation. The first day of menstruation is the first day of a monthly cycle and the whole process begins again. When Pregnancy Occurs When the egg enters the pelvic area it is swept into one of the fallopian tubes by fingerlike projections called fimbria. Sperm travels up the fallopian tube by way of cervical fluid.
Fertilization occurs in the outer portion of the tube when the sperm penetrates the egg.
The now fertilized egg will travel down to the uterus which takes approximately 6 to 8 days and will burrow into the uterine lining. HCG communicates to the corpus luteum to stay alive longer than the normal 12 to 16 days. All rights reserved.