A menstrual cycle in which the ovary does not release an egg.
Why it matters for PCOS
In a typical cycle, one follicle matures and releases an egg (ovulation) around mid-cycle. When anovulation happens, this process does not complete, so no egg is released and progesterone does not rise as it normally would. In PCOS, hormonal imbalance frequently disrupts this follicle maturation, which makes anovulation a common reason for periods that are infrequent, irregular, or absent, as well as for difficulty conceiving.
A doctor can assess anovulation from your cycle pattern, a progesterone blood test in the second half of the cycle, or ultrasound monitoring. It is interpreted together with your symptoms, menstrual history, and other test results, not as a single number.
This glossary is education, not diagnosis. For your own situation, ask a doctor or pharmacist.