The 36-day pregnancy conception time is around the first day of the last menstrual period, but you need to go to the hospital for an ultrasound to check the exact time. For women who have a regular menstrual cycle, the first day of the last menstrual period is basically the time of conception. However, there is a margin of error of about one week because the process of conception is relatively complex, and it takes a certain amount of time for the sperm and egg to move and combine with each other, so there is a certain amount of error in this calculation. If you want to determine the exact time of conception, you need to go to the hospital to be tested by advanced medical equipment. Generally, the pregnancy sac can be seen after 36 days of pregnancy, and the approximate time of conception can be estimated by the size of the sac, the length of the top hip, etc. This accuracy is higher than that of calculating the last menstrual period. 36 days of pregnancy belongs to the early stage of pregnancy, pregnant women need to pay attention to maintaining balanced nutrition and go to the hospital for regular checkups.