After a woman becomes pregnant, the endometrium is thickened, but the endometrium reaching 1.0 cm is not an accurate standard for determining pregnancy. During the menstrual cycle, the endometrium appears with the changes of estrogen and progesterone, and the three stages of proliferation, secretion and menstruation change. The endometrium loses the support of estrogen and progesterone to shed and form menstruation, and the endometrium will reach about 1.0cm in the late stage of secretion, which indicates the imminent menstruation. If you do not have a period and have a history of sexual intercourse, then you should also be alert to the possibility of pregnancy. In this case, it is recommended to go to the hospital for urine pregnancy test, blood chorionic gonadotropin test and ultrasound, if they are all positive (+), then there is a possibility of pregnancy, otherwise, let it be natural and wait for the period to come