A healthy range for endometrial thickness is approximately 1 to 16 millimeters for premenopausal women, depending on the menstrual cycle stage, according to the International Asherman's Association. In postmenopausal women, a thick endometrial, or uterine, lining can be a sign of uterine cancer, states WebMD.
In premenopausal women, endometrial thickness is typically 1 to 3 millimeters after menstruation ends, notes the International Asherman's Association. It is about 6 to 8 millimeters by ovulation, when the egg is released from its follicle. By day 28 of the cycle, the endometrium is between 10 and 16 millimeters thick. Once menstruation starts, it takes about five to seven days to shed the lining.