Most of the 36 days of pregnancy are in the condition of about 20 days of coitus. The calculation of the corresponding gestational week is based on the last menstrual period and is determined by ultrasound examination of the size of the gestational sac. Under normal circumstances, conception occurs at the time of intercourse, which is basically the period of ovulation, when sperm and egg cells come into contact with each other to form a fertilized egg. However, the calculation of the gestational week is based on the first day of the last menstrual period as the standard, the corresponding stage to ovulation in most of the 16 days. So the clinical indication of 36 days of pregnancy is actually about 20 days of conception with intercourse. The specific situation needs to be determined by ultrasonography, observing the size of the gestational sac. If the menstrual cycle is regular, the development of the gestational sac can be determined by the week of gestation and the size of the actual gestational sac. Pregnant women should pay attention to the prenatal examination during pregnancy, actively listen to the advice of professional doctors to do a comprehensive nursing care, pay attention to rest, at the same time, should relax, avoid tension, anxiety, any discomfort should be timely to the hospital, the doctor to clarify the diagnosis, and cooperate with the doctor to deal with the symptoms.