In the first stage, your brain's pituitary gland signals the ovaries to produce a follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These hormones stimulate at least one follicle to develop a mature ovum or egg. As the egg matures, the follicle releases the estrogen hormone, which feeds the lining of the uterus causing it to grow and thicken.
The ovulation stage comes next. This is when the egg is released from the ovarian follicle, gets drawn into the fallopian tubes and starts heading for the uterus. It takes the egg a few days to actually reach the uterus.
Most women do not notice when they ovulate, but some do feel slight abdominal discomfort. You might also have watery vaginal discharge at this stage, which is caused by high estrogen levels. The follicle releases the progesterone hormone at the end of the ovulation stage, which further strengthens the lining of the uterus.
During stage three, you may notice sticky vaginal discharge. If a sperm is present when the egg is traveling own the fallopian tube, fertilization can occur. If it does, the uterine lining is ready to accept and nourish the fertilized egg. (Remember: You can get pregnant anytime there is a ripe egg in your fallopian tube or uterus and there are sperm around to fertilize the egg.)
If the egg is not fertilized, it disintegrates and flows out the vagina, usually before your period. For the next 12 days, the follicle slows down its production of estrogen and progesterone.
At the final stage of the cycle, your period arrives. Menstruation occurs when the uterus sheds its lining. As it stops being nourished by hormones, the lining weakens and deteriorates. Once you get your period, the entire cycle begins again.
