Expected date of delivery, as the name implies is expected date of delivery.
       If pregnant women can remember the end of the menstrual cycle date, you can estimate the expected date of childbirth.
       A fertilized egg develops into a mature fetus from the last menstrual period before conception of the first day of pregnancy for an average of 40 weeks or 280 days, as the saying goes "the pregnancy in October, day of birth," here "month" refers to the gestational age, in 28 days for the calculation of a pregnant month.
       The calculation of the pre birth period is: the last menstrual month plus 9 or minus 3, date plus 7。
       For example, women in the first day of the last menstrual period in January 1, 2006, the date of childbirth should be calculated:
       1+9=10
       1+7＝8
       Its due date is 2006 of October 8th.
       Women in the first day of the last menstrual period in December 20, 2005, the date of childbirth should be calculated:
       12-3=9
       20+7＝27
       Its due date is 2006 of September 27th.
       If a pregnant woman can not remember the last menstrual period, menstruation or not, by the doctor according to the pregnancy reaction occurring time, quickening the start time, hand measured fundus height, the length of uterus to estimate size measurement.
       If pregnant women only remember the last menstrual period of the lunar calendar (lunar calendar) date, it shall be converted into Gregorian date, then estimate.
       Generally 60% of people in the pre delivery period before and after childbirth in 1 weeks, and about 90% of people in the pre delivery period before or within 2 weeks after delivery in 3 weeks. Only 5% of people in the pre delivery date of childbirth, such as irregular menstruation, labor may be longer than the pre delivery period.
       Seen in this light, the pre birth period can remind pregnant women born in the time range, but do not look forward to the birth date so precise. Close to the pregnant women should be ready to delivery at any time.