"Ask Dr. Cook" is a series of questions and answers regarding endometriosis. The current subject and answer can be found on Current Ask Dr. Cook web page. The questions may represent a summary of questions I have been asked by several different patients. I hope you find this information helpful. If you have a question you would like answered, please Submit A Question.

Insulin Resistance, Part I

Question:
I am trying to get pregnant and have endometriosis. My doctor treated my endometriosis but told me that I also have PCOS and might have to take fertility drugs to get pregnant. What is PCOS and do I need to take fertility drugs?

Answer:

PCOS stands for PolyCystic Ovarian Syndrome. Women with this condition often have multiple small functional (follicular cysts or egg sacs) cysts and irregular periods. We have known for a long time that women with PCOS have a normal amount of eggs in their ovaries, but have a hormone imbalance that often prevents complete maturation and release (ovulation) of the egg on a monthly basis. As a medical profession, we have come to realize over the last several years that insulin resistance is an important aspect of this condition.

Symptoms commonly associated with PCOS include irregular cycles, infertility, threefold greater miscarriage rate than the general population, excessive hair growth, acne, weight gain, skin problems and even thinning hair. A woman with PCOS can have what appears to be normal menstrual cycles, but more often experiences infrequent cycles (oligomenorrhea) or frequent bleeding. Remember that a normal menstrual cycle is a result of cyclic fluctuation of the estrogen and progesterone hormone levels. During a normal menstrual cycle a dozen or so immature eggs are recruited. Of those initially recruited, normally only the strongest survives and ovulates. Part of this survival process involves a conversion in the hormone concentration around the egg, from an androgen (male like) environment to an estrogen (female like) environment. Indeed, a woman's estrogen level rises from the beginning of a new cycle to the midpoint in the month (ovulation). Once the egg is released the cells in the ovary change from producing mostly estrogen to mostly progesterone. The progesterone production lasts for 14 days unless pregnancy occurs. Once the progesterone levels drop, the blood flow of the period begins. In a woman with PCOS, rather than one egg surviving and the rest dying off early, most of the eggs make it half way forming small follicular cysts, maintaining an androgen environment (excess hair growth) and none make it to maturation. As a result, the estrogen levels are lower, the androgen levels higher and progesterone levels are low. Because of the imbalance in hormones, the lining of the uterus (endometrium), grows until it gets thick enough that some of it breaks off and bleeds until more grows to heal over. Depending upon how fast the lining of the uterus is growing it can break off and bleed every couple of weeks, every couple of months or sometimes, doesn't bleed at all.

The irregular bleeding tells us that the ovary is probably not fully maturing and releasing a mature egg any given month. Since there is no mature egg to fertilize (or rarely is) the patient experiences difficulty getting pregnant. In the past the fertility drug Clomid (clomaphine citrate) was used to induce ovulation. More recently studies have shown that insulin sensitizing agents such as metformin provide a equal or better pregnancy rates compared to Clomid while also reducing the elevated miscarriage rate in PCOS patients. Two studies were presented last year at the annual meeting of the Endocrine Society. The first compared ovulation rates of PCOS patients using metformin verses those using Clomid. The ovulation rate of the metformin patients was 82% while the Clomid group was 78%. The pregnancy rate was 63% in the metformin group and 36% in the clomid group, although the difference was not statistically significant. Another study at the same meeting demonstrated a miscarriage rate of approximately 9% compared to a 42% rate in patients not taking metformin.

Excessive hair growth, acne and thinning hair are a result of increased androgen levels. Remember a lot of partially developed eggs produce primarily androgen (male hormones) as opposed to a fully mature egg that produces primarily estrogen (actually its the cells surrounding the egg that produce the hormones, not the egg itself)

It is now apparent that as many as one in three Americans have insulin resistance syndrome. Insulin resistance syndrome has also been referred to as Syndrome X or metabolic syndrome. A committee of experts from several leading medical organizations met last month to discuss insulin resistance. Next week I will discuss other aspects and health risks of insulin resistance.

Updated October 29, 2005