How Metabolic Dysfunction Undermines Fertility in Both Sexes

Infertility affects a growing share of couples, and reproductive endocrinologists are pointing to metabolic dysfunction as a central, often overlooked driver. According to Dr. Natalie Crawford, a reproductive endocrinologist and fertility specialist, one in five couples trying to conceive for the first time in the United States will not succeed within 12 months. The conditions shaping that outcome, including insulin resistance, chronic inflammation, and hormonal imbalance, are the same conditions that define a broader metabolic crisis. Understanding the biological links between metabolism and reproduction may matter as much as any specific fertility intervention.

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Insulin resistance sits at the center of the metabolic-fertility connection, particularly for women. According to Crawford, over 80% of women with polycystic ovary syndrome (PCOS) have insulin resistance, and this holds regardless of body weight. The mechanism is specific: in a high-insulin environment, the ovary shifts its hormonal output away from estrogen and toward testosterone. That testosterone creates a toxic follicular environment that delays or prevents ovulation entirely.