Sex Ed Review

The menstrual cycle is a complicated process involving many different hormones, women's sex organs and the brain. The activity of a woman's sexual organs, including their development is under the control of a small gland at the base of the brain, called the pituitary gland. Two of the most important hormones of the pituitary gland are Follicle Stimulating Hormone (F.S.H.) and Luteinising Hormone (L.H.). This is where the Lupron comes into play. It basically blocks the communication between the pituitary gland and the ovaries so that the body does not do its natural cycle and secrete FSH and LH. The Follistim (manufactured FSH) and Repronex (manufactured FSH and LH) are used to simulate the cycle but in much larger quantities.

A woman has 2 ovaries in her reproductive system, each one stores thousands of follicles, within these follicles are the immature eggs. More than one follicle may start to develop at a time, but usually (naturally) only one reaches maturity each month. With the stimulation drugs, multiple follicles will develop and contain eggs that will reach maturity.

At the start of each menstrual cycle the pituitary gland releases F.S.H. which makes the follicles (containing the immature eggs) grow (this is why F.S.H. gets it name). While the follicle is developing, the cells around the egg produce the female hormone - estrogen. This is why the doctor monitors my estradiol (a form of estrogen) level. The higher it is, the more follicles I should have or the bigger my follicles should be. Along with the blood test, ultrasounds are done to follow the number and growth of the follicles. The follicles look like fluid filled blisters on the ovary.

Once the follicle has reached a certain size and development, the rising level of estrogen in the blood, signal to the pituitary gland that the ovary is ready to release the egg. The pituitary gland then sends out a high level of the hormone L.H. (this is commonly known as ‘the L.H. surge’) and this signals the ovary to release the egg (ovulation). The follicle bursts and the egg leaves the ovary and travels through one of the fallopian tubes to the uterus. This is where IVF really intervenes in the natural cycle. When the doctor decides my follicles look like they are at the right size and development, I will be ready to have my egg retrieval. Since I'm taking the Lupron, the estrogen won't signal the pituitary to release the egg. So 36 hours before my egg retrieval I will take one last shot of Human Chorionic Gonadotropin (hCG). This will push the eggs to their final state of maturity so that they will be ready to be put with sperm when they are retrieved. At the egg retrieval, a vaginal ultrasound probe with a guided needle attached to a vacuum tube system is used to aspirate the fluid from the follicles into test tubes, one by one, until they are all gone. These test tubes are passed to the laboratory where the embryologists look through the fluid under microscopes to find the eggs. Technically, there should be one egg per follicle, but a lot of times not every follicle will contain an egg.

The cluster of cells, which formed the follicle, now called a corpus luteum remains in the ovary and starts to produce the female hormone - progesterone.

If a woman has sexual intercourse with a man at this time and his sperm fertilizes the egg, the woman becomes pregnant. The fertilized egg attaches to the uterus and the corpus luteum keeps producing all the progesterone needed, to keep the egg implanted and growing (click here to read more about fertilization). Progesterone also blocks the release of more hormones (L.H. and F.S.H.) from the pituitary gland so that further ovulation does not occur during pregnancy.

If after a few days, no egg is implanted the corpus luteum stops producing hormones and gets reabsorbed in the ovary. The levels of progesterone and oestrogen fall and the lining of the uterus starts to break up. The unfertilized egg and the lining of the uterus are released through the vagina as your "Period." The cycle then starts all over again.