It is normal for a baby to be born 259 days after coitus, and it is normal for it to be born 1-2 weeks before or after the expected date of delivery.
The total number of days of pregnancy is 280, and the first day of pregnancy is counted from the first day of the last menstrual period, the method of calculating the due date is the month of the last menstrual period minus 3 plus 9, and the date will be added to 7, so that you can project the due date. The due date is just a projection, so births within 2 weeks before or after the due date are normal.
Therefore, 259-280 days after intercourse is within the normal date, so it is normal to have a small baby born at 259 days after intercourse, which is already a full-term baby.
During pregnancy, you should pay attention to do a good job of all the labor and delivery examination work, but also pay attention to dietary nutrition supplement, eat more food containing high protein, if the body is not feeling well, you should also consult a doctor in a timely manner.