Calculation of the expected date of delivery, method of calculation of the expected date of delivery

Pregnancy is counted from the first day of the last menstrual period, the month is minus 3, and the day is added to 7, which is the due date of the pregnant woman, and then the number of days of pregnancy is clear at a glance!

For example. Pregnancy is from December 28, the first day of the last menstrual period.

So. The due date is September 4 of the following year.

The normal time limit of pregnancy for human beings is about 40 weeks, and the first day of the last menstrual period is often used to calculate the start time of the expected date of delivery, and the normal pregnancy time limit is about 265 days (referring to the day when the egg is fertilized), and ovulation is in the middle of menstruation, so 40 weeks (280 days) of pregnancy is 2 weeks longer than the pregnancy time calculated from the beginning of actual egg fertilization. If a woman's menstruation is 28 days as a menstrual cycle, then 280 days of pregnancy is equivalent to ten gestational months (28 days is a menstrual cycle) or ten menstrual cycles, so there is a saying that the pregnancy is in October. The due date is only an estimate, and the actual delivery time is often 1-2 weeks different from the due date.

The estimation is based on the entire gestation period of 280 days. The specific method is: due date month Month of the first day of the last menstrual period +9 or -3, Number of days of the expected date of delivery Number of days of the first day of the last menstrual period +7.

In this way, the calculated time is the due date. For example, if the last menstrual period is on February 1, then the month 2 November 9 November, the date 1 October 7 8, then the expected date of delivery should be November 8. If the last menstrual period is after April, it is calculated by minus 3.

For example, the last menstrual cramp is April 2, that is, April - 3 January of the following year, 2 10 7 9 days, that is, January 9 of the following year is the expected date of delivery. If calculated in the lunar calendar; The month is calculated the same, except that the date plus 7 days is changed to add 15 days.

It is estimated that your due date is May 2nd next year.

Mine is also calculated in this way, the expected date of delivery is December 17, and the result is my son who was born on the 16th. ^_

40 weeks, the expected date of delivery is calculated from the date of the first day of the last menstrual period.

The due date is calculated as the number of months of the last menstrual period plus 9 (or minus 3) and the number of days plus 7

A full-term pregnancy lasts about 280 days (about 40 weeks), and all births at 38-42 weeks of pregnancy are full-term pregnancies.

Giving birth within two weeks before or after the expected date of delivery is normal.

Introduction: Because it is difficult for every pregnant woman to accurately judge the time of conception, it is medically stipulated that the expected date of delivery is calculated from the first day of the last menstrual period, and the entire pregnancy period is 280 days, 10 gestation months (each gestation month is 28 days). Let me introduce you to the calculation method of the due date, let's find out together!

1.Last menstrual period is calculated

The due date is calculated by adding 9 or subtracting 3 to the last menstrual period, and adding 7 to the day. If you use the lunar calendar, the month is calculated in the same way, and 15 is added to the day instead.

2.Fetal movement time inference algorithm

The time of fetal movement in primiparous women is generally between 18 and 20 weeks, and the time of fetal movement in pregnant women who give birth again is generally two weeks earlier than that of first-time mothers, so at 16-18 weeks. The fetal movement can be fetal movement at that time, so the formula for calculating the expected date of delivery is: due date of primiparous women = date of fetal movement + 20 weeks.

Due date of multiparous women = date of onset of fetal movements + 22 weeks.

3.Body temperature curve inference algorithm

The lowest segment of the basal body temperature curve is the time of ovulation of the woman, and the last day of the low temperature segment of the basal body temperature curve can be used as the ovulation day, and 264-268 days from the date of ovulation can be extrapolated, or 38 weeks.

Supercheck inference algorithm

The doctor can estimate the gestational age and calculate the expected date of delivery by measuring the diameter between the biparietal head of the fetal head, the length of the head and the hip and the length of the femur.

5.Early pregnancy response inference

Early pregnancy reactionMorning sickness generally occurs about 42 days after the last menstrual period, and 280 days backwards is the expected date of delivery, so the calculation formula should be the expected date of delivery = the date of first pregnancy reaction + 34 weeks.

6.Fundal height inference algorithm

If the time of a woman's last menstrual period is not clear, the expected date of delivery can be determined according to the height of the uterine fundus, and this calculation is generally only known to professionals.

7.Pregnancy calendar algorithm

Using a commercially available pregnancy calendar in the form of a simple or disc, the number of weeks of pregnancy and the expected date of delivery can be calculated by comparing the date of the last menstrual period. This method and the inverse menstrual algorithm may differ by day.

Generally speaking, it takes 280 days to get pregnant, and 28 days is medically counted as an obstetric month, and 40 weeks of pregnancy is 10 obstetric months.

Therefore, it is also called "October pregnancy"). The due date is calculated from the first day of a person's last menstrual period, the number of months is added by nine or minus three, and the number of days is added by seven.

If the expectant mother adds fifteen, it is the expected date of delivery of the lunar calendar. The calculation of the due date is only an approximate estimate. According to the actual situation of the mother, it can be before and after.

It can be about seven days apart. If you usually menstruate, the cycle is short, less than a month, and the days of labor are mostly before the expected date of delivery; If the menstrual cycle is usually long, about 40 days, most of the days of labor are after the expected date of delivery.