An endometrium of 11mm without a period may be pregnant, but it may not be pregnant. It can be determined by blood HCG, urine HCG or gynecological ultrasound, and then treated accordingly. If a woman has a regular menstrual cycle and is having a normal sex life, and has 11mm of lining without a period, it may be an early sign of pregnancy. In the early stage of pregnancy, the fertilized egg is late, the gestational sac has not yet formed, and the gestational sac is not yet visible inside the endometrium, which only shows the thickening of the endometrium. If your period is delayed for a long time, more than 10 days or longer, pregnancy is more likely. You can use urine HCG test paper, if it is positive, it means you are pregnant; if it is negative, you can go to the hospital to have blood HCG test, because there are false negatives in urine test paper, blood HCG test is more accurate. If the blood HCG value is elevated, it proves pregnancy and a gynecological ultrasound can be performed. However, if the endometrium is 11mm and there is no menstruation, it may not be pregnancy, but physiological endometrial thickening. The thickness of the endometrium will change with the menstrual cycle. Generally, the endometrium will thicken in the late menstrual period in order to accommodate the implantation of a pregnant egg, and if it does not implant, it will peel off and menstruate. In addition, some pathological thickening should be excluded, such as polycystic ovary syndrome, endometrial polyps, submucosal fibroids, ovarian malignant tumors, etc., which may lead to abnormal thickening of the endometrium. In these cases, endometrial thickening may be simple thickening, complex thickening, and some may be atypical thickening or hyperplasia, requiring diagnostic scraping or hysteroscopy to remove the endometrium for further examination and clear diagnosis before surgery or other treatment.