An endometrial thickness of 0.9 three days past your period is not normal. Normally, the thickness of the uterine lining is about 0.4 centimeters just after menstruation. About 8 to 21 days after menstruation, the thickness of the uterine lining is about 0.5 to 0.9 centimeters, so 0.9 centimeters of endometrial thickness three days after menstruation is not normal. Endometrial thickness and cyclic changes with the endocrine hormone levels and cyclic changes, the general endometrial thickness of more than 1.5 centimeters is considered endometrial thick, if there is an abnormal proliferation of the endometrium, you can consider the use of progesterone to do medication scraping. It is recommended to go to the regular hospital to check the endocrine hormone levels to see if there is an abnormality, if there is an abnormality, you should actively cooperate with the doctor’s treatment.