Checking the week of pregnancy can be calculated on the basis of the last menstrual period, or it can be judged by the size of the gestational sac shown by ultrasound. Pregnant women can choose the appropriate method of determination according to their specific situation. For women with regular menstrual cycles who have a history of sexual intercourse, it is possible to detect pregnancy through urine after 5-7 days of delayed menstruation, and the week of pregnancy is calculated from the first day of the last menstrual period, not from the time of conception during intercourse. For women who usually have irregular menstrual cycles, the actual time of pregnancy may not coincide with the time of menopause. You can consider checking the ultrasound around 50 days after menopause to check the size of the gestational sac, and then project the exact week of pregnancy based on the size of the sac. Ultrasound used for early pregnancy diagnosis can take two forms: transabdominal ultrasound and transvaginal ultrasound. For pregnant women without vaginal bleeding, vaginal ultrasound can be used, and if transabdominal ultrasound is needed, you usually need to drink 500-700ml of water within 30-60min before the examination, and prohibit urination 2-3h before the examination to keep the bladder full. If the difference between the gestational week calculated by the last menstruation and the ultrasound is less than 1 week, both are more accurate; if the difference is more than 1 week, the ultrasound prevails.