How thick does the endometrium need to be for menstruation to occur?
Jul 10, 2025
Source: Cainiu Health
Dr. Zhang Lu
Introduction
Under normal circumstances, when the endometrial thickness reaches 10 to 14 millimeters, a woman will experience menstruation. However, this value is not fixed and can be influenced by various factors. If there is menstrual delay, amenorrhea, prolonged menstrual bleeding, or abnormal uterine bleeding, regardless of endometrial thickness, medical treatment should be sought and managed under a doctor's guidance; self-diagnosis or delaying treatment is not recommended.
Generally, when the endometrial thickness reaches 10-14 millimeters, women will experience menstrual bleeding. However, this measurement is not fixed and can be influenced by various factors. Detailed analysis is as follows:
Most women will have an endometrial thickness of 10-12 millimeters before the onset of menstruation. In some women, the endometrium may reach 10-15 millimeters or even 14 millimeters in thickness before menstrual bleeding begins. Due to individual differences among women, endometrial thickness varies from person to person. Some women may still menstruate even with slightly thinner or thicker endometrium, depending on their own physiological characteristics and hormone levels. Abnormally thickened or excessively thin endometrium may indicate underlying health issues, such as polycystic ovary syndrome, endometrial polyps, uterine fibroids, or hormonal imbalances, which may affect the menstrual cycle and fertility.
If there is menstrual delay, amenorrhea, prolonged menstrual bleeding, or abnormal uterine bleeding, medical treatment should be sought regardless of endometrial thickness. Self-diagnosis or delaying treatment is not recommended.
