Anovulation

Anovulation is the absence of ovulation during a menstrual cycle. It can result in irregular or absent menses and is a common cause of infertility in reproductive-age people. Anovulatory cycles may still produce uterine bleeding if estrogen levels are sufficient, but they do not release an egg.

Causes are diverse and typically relate to disruptions of the hypothalamic-pituitary-ovarian axis. Common conditions include polycystic ovary syndrome (PCOS), hypothalamic or pituitary disorders, thyroid dysfunction, and hyperprolactinemia. Lifestyle factors such as significant weight loss or gain, extreme exercise, and stress can contribute, as can certain medications. Primary ovarian insufficiency and advanced age can also lead to persistent anovulation. The underlying cause often guides management.

Diagnosis relies on history and targeted testing. Clinicians assess menstrual pattern and fertility goals, perform a pregnancy test, and measure serum progesterone in the luteal phase to confirm whether ovulation occurs. Additional tests may include levels of LH, FSH, prolactin, and thyroid hormones, along with assessment for insulin resistance or hyperandrogenism. Pelvic ultrasound can help evaluate ovarian morphology in suspected PCOS.

Treatment focuses on the underlying cause and the patient’s goals. Lifestyle modification and weight management can restore ovulation in some PCOS cases. Ovulation induction is used for infertility, with first-line agents such as letrozole or clomiphene citrate, and alternative therapies include gonadotropins or pulsatile GnRH in resistant cases. Treatment may also address associated conditions (thyroid disorders, hyperprolactinemia) and metabolic risks.