Insulin resistance means the body's cells respond less effectively to insulin, so the pancreas produces more of it to keep blood sugar in range. Over time this can raise the risk of prediabetes and type 2 diabetes.
It is common in PCOS (in both higher-weight and lean women) and can worsen symptoms by driving the ovaries to make more androgens. The same habits that improve insulin sensitivity — a balanced lower-glycaemic diet and regular activity — are central to managing PCOS. See PCOS and insulin resistance.