Inaccurate menstruation can be estimated by ultrasound examination and symptoms of pregnancy under the guidance of a doctor. 1. Ultrasound examination: Pregnant women with inaccurate menstrual cycles can use ultrasound examination under the guidance of a doctor to estimate the expected date of labor. If there is an ultrasound in early pregnancy, the week of pregnancy can be checked according to the size of the gestational sac and buds, the length of the head and buttocks and so on, and the expected date of labor can be estimated; in the middle and late pregnancies, the ultrasound should be combined with the ultrasound indication of the size of the fetus to check the week of pregnancy in general. 2. Symptoms of pregnancy: If there is no early pregnancy ultrasound, the last menstrual period is not known, but also according to the pregnant woman’s own symptoms of the time to roughly estimate. Such as early pregnancy reaction will generally appear in about 6 weeks after menopause, most pregnant women will be consciously in about 20 weeks of pregnancy to the fetal movement, etc., can also be roughly projected to the week of pregnancy.