Ovarian Factor Infertility
Women are born with their lifetime supply of eggs within the ovaries. During each monthly menstrual cycle eggs develop within the ovarian follicles under the influence of the hormone FSH. Once the egg matures, ovulation is triggered by the hormone LH. Ovulatory dysfunction is the most common type of ovarian factor infertility.
Ovulation may occur irregularly (oligoovulation) or not at all (anovulation). The ovulatory process is under the control of numerous interrelated hormones. The hypothalamus is located at the base of the brain and it produces gonadotropin releasing hormone (GnRH). GnRH travels through the blood stream to the pituitary gland where it stimulates the production of FSH and LH.
FSH stimulates the recruitment and development of eggs within the ovarian follicles. As healthy eggs develop they produce increasing amounts of the hormone estrogen. Estrogen stimulates the development of the lining of the uterus (endometrium) and provides “feedback” to the hypothalamus. Once the eggs mature a surge of leutinizing hormone is released by the pituitary causing ovulation to occur.
After ovulation, the remaining follicle becomes a structure known as the corpus luteum which begins to produce progesterone. Progesterone further supports the development of the endometrium and the developing fetus.
Anovulation can be caused by numerous factors including stress, pituitary disorders, obesity, anorexia, polycystic ovarian disease, disorders of the adrenal or thyroid glands, elevated levels of prolactin, and others. The reproductive endocrinologist orders the appropriate tests to determine the cause of anovulation prior to treatment.
Many times Clomid is administered to stimulate ovulation. Clomid works at the hypothalamus causing an increase in GnRH. Once ovulation is occurring there is no value to increasing the dosage of Clomid and it should not be used for more than 3-6 ovulatory cycles. Studies clearly indicate that there is little chance of conception beyond three cycles.
Injectable FSH is used in stimulated IUI and in assisted reproductive technology cycles (IVF). FSH directly stimulates the ovaries and causes the production of numerous eggs. FSH is also very effective in treating women who have certain disorders such as hypothalamic amenorrhea. This drug should only be administered by a reproductive endocrinologist thoroughly trained in its use.
A condition termed hyperprolactinemia (elevated prolactin levels) is a cause of anovulation that is often accompanied by breast milk production. Prolactin levels normally rise during pregnancy to stimulate breast milk production. This condition is usually caused by a small tumor located at the base of the pituitary gland. It can often be treated with medication (Parlodel, bromocriptine) or the tumor is surgically removed.
Polycystic ovarian syndrome (PCOS) is a cause of anovulation and is accompanied by elevated androgen (male hormones) levels. Women with PCOS typically have excess body hair and a classic “pear shaped” body appearance. The syndrome is evidenced by the production of numerous small cysts on the ovaries. Clomid is sometimes used to induce ovulation and more recently Glucophage (metformin) has demonstrated excellent results. See the section of PCOS for more information.
As a woman approaches menopause, her eggs loose there capacity to develop and fertilize. The period preceding menopause is termed the perimenopause and is evidenced by irregular ovulation. Ovarian reserve is a measure of a womens ability to produce viable eggs as indicated by day 3 FSH/LH levels and the clomiphene citrate challenge test. Ovarian failure is the inability to produce viable eggs.
There are other complex causes of ovulatory dysfunction and ovarian failure. A reproductive endocrinologist should be consulted early in the evaluation so a specific cause can be identified and the best treatment(s) initiated.
When viable eggs cannot be produced and ovulated the best hope for a couple to create a genetically related child is to use donor eggs.