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How can polycystic ovaries contribute to irregular ovulation?

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Diagram showing the female reproductive system with labeled ovaries, fallopian tubes, uterus, and vagina, alongside hormone pathways and the process from ovulation to fertilization and early embryo development. — infertility Major structures and hormones involved in the initiation of pregnancy. Also seen, at right, is the development of an egg cell (ovum) from follicle to embryo.

Polycystic ovary syndrome (PCOS) contributes to irregular ovulation through a complex hormonal imbalance that disrupts the normal menstrual cycle.1

The condition is primarily driven by an excess of androgens and often involves insulin resistance. This resistance leads to hyperinsulinemia, which stimulates the ovaries to produce even more androgens. These elevated androgen levels, combined with increased conversion of androgens to estrogens in adipose tissue, cause a sustained increase in the secretion of luteinizing hormone (LH) from the pituitary gland.1

This abnormal hormonal environment suppresses ovulation, leading to menstrual irregularities such as oligomenorrhea (infrequent periods) or amenorrhea (absence of periods). Ultimately, this disruption of the gonadotropin release cycle prevents the proper maturation and release of eggs, which is a significant factor in infertility associated with the disorder.12