Normally, women are born with a finite supply of eggs in their ovaries. Each month a dominant follicle (each follicle contains one egg) develops to maturity and an egg is ovulated. Ovulation is controlled by complex hormonal interactions involving the hypothalamus and pituitary gland, interacting to produce follicle stimulating hormone (FSH) and luteinizing hormone. FSH and LH travel to the ovaries via the bloodstream where they stimulate the ovaries to develop eggs and produce estrogen.
The hypothalamus is located at the base of the brain and works much like a thermostat. It measures the levels of various hormones and adjusts their production in a “feedback mechanism”. The hypothalamus releases gonadotropin releasing hormone (GnRH), which stimulates the pituitary gland to produce FSH. FSH causes the recruitment of follicles and supports them as they grow. As normal follicles develop they produce the hormone estrogen, which, among other actions stimulates the growth and increase in vascularity of the endometrium. The endometrium must develop to support embryo implantation and the development of the fetus.
Drugs like Clomiphene Citrate work at the hypothalamus where it competes with estrogen for the estrogen receptor. This competition causes the hypothalamus to signal the release of more FSH. Injections of FSH directly stimulate the ovaries while bypassing the hypothalamus and the pituitary.
The hypothalamus reacts to the levels of estrogen in the blood and adjusts the production of FSH. Once estrogen and FSH levels reach appropriate levels, the hypothalamus releases a bolus of GnRH causing a surge in luteinizing (LH) hormone from the pituitary gland. This surge causes the egg to be “ovulated” from the follicle in approximately 36 hours. After fertilization, the embryo hopefully implants in the endometrium and continues development. The follicular structure left after ovulation becomes the corpus luteum, which produces progesterone to further support the endometrium. As the placenta develops, it also produces progesterone and eventually replaces the corpus luteal produced progesterone.
As women age, egg quality declines until the menopause is reached and no ovulation occurs. Some women experience premature menopause, which is accompanied by elevated FSH levels, irregular or absent periods, and a cause of infertility in women.
Donor egg IVF is an option for women with ovarian failure. The eggs of a younger woman are used in an in vitro fertilization cycle and success rates are high equaling that of the egg donor’s age group. Our Louisiana donor egg program serves patients from Baton Rouge, New Orleans, and the surrounding regions. The good news is that donor egg success rates equal the age of the egg donor. For example, if the eggs of a 22 year old are used in an IVF cycle and the resultant embryos placed in a 40 year old mother, the success rates equal the 22 year old age group. We have a variety of egg donors from all ethnic backgrounds to choose from.