PCOS Part 2: How Insulin Effects Ovarian Funciton

Part 1, for anyone who hasn’t had a chance to read it, is all about how it is the negative effects of insulin resistance and elevated insulin levels that causes the weight gain we often associate with PCOS. As insulin levels rise, it triggers the production of increased androgrens in the developing follicles of the ovary. The way the system should work is that each month we usually select one egg and that egg becomes a dominant follicle and then, when the follicle matures, the egg is released to be picked up by the fallopian tube.

In patients with PCOS, this process is altered. In reality, it’s not just one egg thats recruited, but about a dozen. Generally, only one makes it across the finish line (if there are more, that’s how you get twins). In PCOS when you have these dozen follicles competing, insulin comes in and halts their maturity and converts them to factories for making testosterone. Elevated testosterone then causes things like hair growth in places you don’t want it, but it’s also anabolic steroid meaning that it makes it easier for you to gain weight and muscle - the last thing anyone with PCOS wants any help with. These follicles then end up in a sort of arrested development and rarely proceed to the dominant follicle and ovulation phase.

By reducing insulin levels in the body, you are allowing the system to work the way it normally would and we are pretty sure that’s why adding metformin to a clomid or letrozole regimen helps women with PCOS. (Clomid works by hiding estrogen from the brain and getting it to make more FSH and letrozole works by decreasing the conversion of estrogen to testosterone in ovary so you make it all the way to the mature follicle stage.) It’s also why I recommend that anyone with PCOS who is trying to get pregnant will be best served by eating a strict low carb diet in order to help keep insulin levels as low as possible.