The part of the menstrual cycle after ovulation until the next period, usually 12 to 14 days.
Why it matters for PCOS
The luteal phase is the second half of the menstrual cycle, beginning after ovulation and ending when a period starts. Once an egg is released, the leftover follicle becomes the corpus luteum and produces progesterone, the hormone that stabilises the uterine lining to support a possible pregnancy. If no pregnancy occurs, progesterone falls and a period begins.
In PCOS, irregular or absent ovulation makes the luteal phase hard to identify, because it only exists once true ovulation has happened. Long cycles without ovulation mean less progesterone is produced, which is part of why periods become irregular. A blood progesterone test timed to the right point in the cycle can help show whether ovulation occurred, but the timing and interpretation depend on your cycle length and are judged by a doctor.
This glossary is education, not diagnosis. For your own situation, ask a doctor or pharmacist.