I've read much of the material you've written concerning polycystic ovarian syndrome (PCOS). You mentioned PCOS briefly in your column on Causes of Miscarriage, where you said one hormonal cause was "high levels of the hormone LH associated with PCOS." I'm curious about the effects PCOS might have on a pregnancy. Is it possible to treat these effects to prevent miscarriage? How likely is it that PCOS will cause miscarriage?

Laurilee

LH (luteinizing hormone) helps stimulate production of estrogen by the growing, maturing egg follicle in the ovary. Once the egg is mature, the LH level spikes, and the egg is released. I like to compare ovulation to rocket launching by NASA. The rocket (egg) is connected to the launch tower (surrounding cumulus cells) by thin connecting tubes. Vital chemical messages (cyclic AMP) are sent between the cumulus cells and the eggs. Moments before launch (ovulation) the countdown reaches zero and the launch button is pressed (LH blood level surges). The connecting cables (cellular connections) disconnect, and the rocket goes on internal power (resumes maturation) and leaps from the pad.

Unfortunately, women with PCOS have an LH level that is higher than normal before the egg is ready to be released from the follicle. That means the egg gets a mixed message. To use the NASA analogy, the rocket goes on internal power and gets ready for launch before being completely fueled. The connections between the cumulus cells and the egg detach prematurely, and the cyclic AMP levels in the egg drop. This interruption in the maturation process can result in abnormal chromosomes in the egg and ultimately increase the risk of miscarriage in PCOS patients to as high as one out of three who conceive.

Treatment with metformin has been shown to lower LH levels in PCOS patients, but our early experience has not shown any reduction in the risk of miscarriage. However, ovulation induction treatments that lower LH levels may reduce the risk of miscarriage for patients with PCOS. One suggested way to minimize the risk is to precede ovulation induction with a month of birth control pills. If pregnancy is not achieved, ovulation induction is alternated with birth control pills. A combined protocol starts with a month of birth control pills, and two weeks later a GnRH-analogue is added. With the menses that follows the end of the pill cycle, injections of FSH are initiated for a period of 8-12 days. This protocol can reduce the risk of miscarriage by 50 percent.