As the cycle progresses and moves towards ovulation, the endometrium grows thicker, up to about 11 mm. About 14 days into a person's cycle, hormones trigger the release of an egg. During this secretory phase, endometrial thickness is at its greatest and can reach 16 mm.
During this timeframe, the uterus is in the proliferative phase. Estrogen induces growth of the functional layer of the endometrial lining, which enables it to grow from about 1-3 mm post cycle to 6-8 mm approximately. Days 12-16 of the menstrual cycle At this point, the endometrial layer is about 6-8 mm thick.
