How many days of normal pregnancy are born?

Under normal circumstances, the expected date of delivery from the beginning of pregnancy to birth should be 280 days. The expected date of delivery is the cycle calculated from the day of the last menstrual period. Calculated based on 28 days per month for a total of 10 months, the entire gestational week is 280 days. It is normal for a baby to be born half a month earlier or half a month later than the expected date of delivery. And ovulation is related to the morning and evening, if ovulation early, may be a few days earlier when the baby is born, if ovulation late, the baby may show delay at birth. And the usual constitution and nutrition is also a certain relationship, and not absolute due date, just a rough day.