It is normal for the endometrium to be 4mm on the second day of menstruation, and patients do not need to worry too much.
Usually, the normal thickness of endometrium is 5-10mm, but with the onset of menstruation, the thickness of endometrium will also change, which is mostly categorized into hyperplasia, secretion and menstruation. Generally, the proliferative phase refers to the 5th-14th day of the menstrual cycle, during which the follicles are gradually developing and the endometrium will gradually thicken from 1mm to 5-10mm.
The secretory phase is the 15th-28th day of the menstrual cycle, during which the corpus luteum is formed and the endometrium can be up to 8-12mm. if the menstrual phase, which generally refers to the 1st-4th day of the menstrual cycle, due to the degeneration of the corpus luteum in this phase and the decrease of estrogen and progesterone secretion, the endometrium is around 4-6mm in this phase. So 4mm of endometrium on the second day of menstruation is considered normal.
It is recommended that women pay more attention to their own situation, if abnormal endometrial hyperplasia occurs, it is necessary to find out the cause of the disease in a timely manner, and reasonably targeted treatment.