How do I know how many days I am pregnant? The number of days to know how many days to be pregnant is calculated according to the last menstrual period, as follows: 1. Normal menstruation and normal ovulation, according to the last menstrual period. 2. Ultrasound to understand the size of the intrauterine gestational sac, to project the time of conception, and use it to project the expected date of delivery. In case of irregular menstruation, you can also calculate the time of conception according to the time of conception during intercourse, plus two weeks. Generally, most women will experience nausea, vomiting, loss of appetite, dizziness, desire to sleep, or sudden desire to eat certain foods, fruits, and acidic things around 36 days of pregnancy.3. Ultrasound after 40 days of menstrual discontinuation is relatively accurate in calculating the days of conception. Pay attention to balanced nutrition during pregnancy and combine work and rest.