What is the normal thickness of the endometrium before menstruation?

Generally, an endometrial thickness of 10-12 mm before menstruation is considered normal. Detailed analysis is as follows:

Endometrial thickness measuring between 10-12 mm before menstruation is typically regarded as normal. During the menstrual cycle, the endometrium undergoes proliferation and secretory changes in response to hormonal fluctuations. As menstruation approaches, the endometrium thickens to an optimal state to prepare for possible implantation of a fertilized egg. A thickness of 10-12 mm provides a favorable environment for embryo implantation and aligns with normal physiological proliferation patterns. With the subsequent decline in hormone levels, the endometrium naturally sheds, forming the menstrual flow. This range ensures regular menstrual onset and stable menstrual volume.

Endometrial thickness dynamically changes throughout the menstrual cycle. Determining its normalcy requires consideration of the specific phase of the cycle and cannot be based solely on a single measurement. If the endometrial thickness significantly deviates from the 10-12 mm range before menstruation—either too thin or too thick—it may indicate hormonal imbalances or endometrial pathology, and timely medical evaluation is recommended. In daily life, maintaining regular作息 (作息 should be translated as "作息" is missing in the provided English context. Please clarify or confirm the intended term.)作息 refers to maintaining regular sleep-wake cycles and lifestyle habits, avoiding excessive fatigue and undue mental stress, which helps preserve hormonal balance and ensures normal endometrial physiology.