A woman who becomes pregnant in December will usually give birth in September of next year. A normal woman will give birth in 10 trimesters, and if she becomes pregnant at the end of December, her due date will be in October of next year. The due date is calculated according to the woman’s last menstrual period, the solar calendar is calculated by adding 9 or subtracting 3 to the month and adding 7 to the date, the due date is only an expected date, it is normal for a woman to give birth two weeks before or two weeks after the due date, it needs to be decided according to the intrauterine condition of the fetus. The woman should pay attention to strengthen the maternity checkup after pregnancy, and regularly do early Down’s syndrome screening, non-invasive DNA test, and ultrasound teratology examination, which will help to find out whether the normal growth and development of the fetus is in line with the pregnancy week and the fetal malformation, so as to deal with the situation as early as possible.