4mm is normal.

Endometrium in different menstrual cycles, membrane thickness is not the same, menstruation is follicular phase, endometrium gradually thickened, to luteal phase to reach the end, menstruation, it will gradually shed, just finished menstruation, that is, menstruation 5~7 days, is the thinnest endometrium. Normally, if in the middle of menstruation, the endometrial thickness can reach 8 mm, it does not affect pregnancy, if the menstruation has just ended, the endometrial thickness is too thick, more than 8 mm is not normal, if the endometrium is 4 mm in the first menstruation, it is normal. But if in the middle of luteal phase, or is the endometrium or 4 mm, it is not normal, indicating that the endometrium has adhesions, or damage, or estrogen is too low. Therefore, simply saying that the intima is 4 mm does not explain the problem, it needs to be seen at what time it is examined.