Insulin resistance is a common feature of PCOS- when more insulin is needed to keep sugars at a normal range. There are not really any great tests for insulin resistance which are widely available, but a 2hr glucose tolerance test can give you an idea. The medication Metformin can help with insulin sensitizing by decreasing glucose absorption, glucose production, and increasing insulin’s ability to uptake glucose. It can also help with weight lost (modestly, and probably somewhat related to its GI effects). While studies are limited in design (obese and lean patients, different tests for insulin resistance and some not tested at all), in women with PCOS Metformin also helps with ovulation compared to placebo and maybe helpful in combination with Clomid for ovulation. This is an important point; we don’t have good studies showing us which populations metformin works best in since not all studies included insulin resistance as a criteria and if they did, they were not uniform in figuring out how someone qualifies for insulin resistance. Furthermore, weight varied which means that some lean PCOS patients can benefit from Metformin for metabolic benefits.
However other medications (Clomid and Femara) are more effective in achieving ovulation, pregnancy, and live birth. Specifically, Metformin has not been shown to increase live birth rates (what we truly care about) in combination with the other medications unless patients have been on it for 3 months. Overall if concerned for insulin resistance Metformin can help, and likely help with ovulation but should not be used alone to help achieve pregnancy.
A leading PCOS expert and an Austin female fertility specialist, Dr. Maya Barsky states “Our goal is a healthy mom and healthy baby so Metformin may be helpful in achieving some of those goals and may be recommended to be used in combination with other treatments.”