A 13mm thick endometrium does not indicate early pregnancy. The endometrium is also thickened before menstruation under the effect of estrogen and progesterone. If there is thickening of the endometrium and delayed menstruation, then it is recommended to use early pregnancy test for more than 14 days of sexual intercourse or go to the hospital for more than 10 days of sexual intercourse to draw blood to confirm whether you are pregnant. After the pregnancy is confirmed, the pregnancy site should be further observed. If bleeding or abdominal pain occurs during this period, it is necessary to consult a doctor promptly, as this situation does not exclude the possibility of biochemical pregnancy or ectopic pregnancy.