Is the expected date of delivery really accurate?

What expectant mothers should pay attention to is that the expected date of delivery can remind the fetus of the time range of safe delivery, not the exact date of delivery.

In medicine, a full-term baby refers to a baby born between 37 and 42 weeks. During this period, 80-90% of babies were born, and premature babies were born before 37 weeks, accounting for 5- 10%. The younger the gestational age, the worse the life ability of premature infants. Therefore, expectant mothers must prevent premature delivery and uterine bleeding.

If the expectant mother has not started the fetus after the expected date of delivery, the expectant mother need not worry, keep calm, do a good job in prenatal examination, be hospitalized after the expected date of delivery 1 week, and have not given birth for more than 42 weeks. Medically, it is called over-pregnancy, which has many hazards. Placenta aging, lack of nutrition and oxygen supply to the fetus, the fetus is easy to stop development or intrauterine hypoxia. If the pregnancy is overdue, the doctor will take measures to terminate the pregnancy.

Therefore, the expected date of delivery is only a reference value, and the elastic time is 4 weeks.

Calculation method of estimated delivery date

Under normal circumstances, doctors calculate the expected date of delivery according to the last menstruation of expectant mothers. Even if the last menstrual period is the first day, 280 days later is the expected date of delivery.

The specific algorithm is to add 9 or subtract 3 to the month of the last menstruation and add 7 to the date. For example, the last menstrual period of expectant mothers is February 1 1, and the expected date of delivery is June 165438+ 10/8. Of course, the premise must be based on the calculation of the 28-day menstrual cycle, so it must be revised according to the length of the individual menstrual cycle.

If the expectant mother forgets the time of the last menstruation, the doctor can also judge the expected date of delivery according to the reference value on the basic body temperature curve method, fetal movement, morning sickness or B-ultrasound data.

For example, calculating the delivery date of morning sickness is not the most accurate algorithm. Generally, morning sickness starts from 4-5 weeks of pregnancy, and 250 days is the expected date of delivery. For example, people who don't have morning sickness, or people whose morning sickness reaction starts late.

Therefore, the accuracy of general B-ultrasound examination is relatively high, and doctors judge the expected date of delivery according to the data such as fetal biparietal diameter, femoral length and amniotic fluid index.

The estimated delivery date may be inaccurate.

The expected date of delivery is calculated according to the publicity. Because the exact time of conception is not easy to grasp, it is stipulated in medicine that the expected date of delivery is calculated from the first day of the last menstruation, and pushed back by about 280 days, that is, 40 weeks of pregnancy, equivalent to 10 month.

The expected date of delivery can be used as a reference, but the baby may not be born on the same day. Statistics show that only 5% of babies are born at the expected date of delivery, and it is normal for the fetus to be born two weeks before and after the expected date of delivery.

The term "fetus" in clinic generally refers to the gestational age between 37 weeks and 42 weeks, during which about 80%-90% of pregnant women give birth. Premature delivery is less than 37 weeks, accounting for about 5%- 10%.

The estimated delivery date is only an approximate range and will not be very accurate. There are few babies born due in clinic. Generally speaking, it is within the normal range to advance or postpone for two weeks.

You can calculate the expected date of delivery according to the time of your last menstruation, or according to your baby's development, especially within 16 weeks of pregnancy. B-ultrasound can calculate the actual gestational age by measuring fetal head circumference and hip circumference.

No matter which method is used to calculate the expected date of delivery, it is an approximate date and will not be completely consistent.

Is the expected date of delivery really accurate?

The expected date of delivery is calculated according to the first day of the last menstruation of pregnant women, and the accuracy is not high. Only 5% of the fetus is born at the expected date. And 95% of babies are born within two weeks before and after the expected date of delivery. In addition to the last menstruation, we can also calculate the expected date of delivery by fetal movement, B-ultrasound, morning sickness, basal body temperature and fundus height.

The common method of expected date of delivery is the first day of last menstruation, month +9 or -3, and days +7. For example, the last menstrual period is February 5, 20 15, so the expected date of delivery is February 5, 20112.

Other methods for calculating the estimated delivery date

Calculate the expected date of delivery by the height of the fundus: the doctor calculates the expected date of delivery by measuring the height of the fundus of the pregnant woman.

Fetal movement is calculated as the expected date of delivery: Fetal movement generally begins at 16- 18 weeks of pregnancy, so the expected date of delivery is the fetal movement day plus 20 weeks for primiparas and the fetal movement day plus 22 weeks for multiparas.

Calculation of the expected date of delivery of morning sickness: 42 days after pregnancy (6 weeks of pregnancy) is 42 days after the last menstruation, and 280 days is the expected date of delivery according to this date. Suitable for mothers who vomit during pregnancy.

Calculate the expected date of delivery with the body temperature curve: the last day of low temperature in the body temperature curve is regarded as the ovulation date, and 38 weeks is the expected date of delivery.

B-ultrasound calculates the expected date of delivery: the doctor will measure the biparietal diameter, abdominal circumference and femur length of the fetus, estimate the gestational age and determine the expected date of delivery. It is more accurate when the fetus is in line with gestational age. If the fetus develops too fast or too slowly, there will be errors.

The expected date of delivery can remind you of the time range of your baby's safe birth, but don't look at the expected date of delivery so accurately.

So how to calculate the expected date of delivery? Is it allowed or not? Let's listen to the opinions of experts.

How to calculate the expected date of delivery?

Because it is difficult for every pregnant mother to accurately judge the time of conception, the method of estimating the expected date of delivery is to start from the first day of the last menstruation, and the whole pregnancy is 280 days, with 10 pregnancy months (28 days per pregnancy month).

Pregnant mommy gave birth within 37.42 weeks of pregnancy, all of which were full-term delivery. The length of menstrual cycle varies from woman to woman, so it is normal that the difference between the expected date of delivery and the actual expected date of delivery is 1.2 weeks.

The main calculation method is as follows:

The month of last menstruation plus 9 or minus 3 is the estimated number of delivery months; Days plus 7 is the estimated delivery date.

For example, Ms. Zhang's last menstrual period was1March 999 13, and the expected date of delivery was about1February 20, 999.

Pregnant mommy can also calculate backwards from the first day of the last menstruation to the 280th day, which is the expected date of delivery.

Is the expected date of delivery accurate or not?

The expected date of delivery can remind you of the time range of your baby's safe birth, but don't look at the expected date of delivery so accurately. According to the statistics of some scientists, only about 50% pregnant mothers give birth in the expected date.

Pregnant mommy should be ready to give birth at any time after 37 weeks of pregnancy, but don't worry too much. Let it be. If there is no sign of delivery in 4 1 week of pregnancy, you should be hospitalized in time for observation or induced labor.

Also, even if the gestational age is accurate, delivery within two weeks after the expected date of delivery has little effect on the fetus, but attention should be paid to fetal movement.

Therefore, because it is difficult for many pregnant mothers to judge the time of conception, the expected date of delivery may not be completely accurate.

The expected date of delivery is only a "predicted date", not a "date of birth". The calculation of expected date of birth is to make preparations within the possible date of birth, so as to avoid being in a hurry and accidents.

So pregnant mothers don't have to worry too much about the expected date of delivery.

I don't know, some people are born when the expected date of delivery arrives, and some people are born around the expected date of delivery. The estimated delivery date can only be used as a reference. Tell us when the baby will come out, and make psychological and material preparations in advance.

My daughter was born half a month earlier than the expected date of delivery, just a few days after full term. I think it should also be related to my physical condition and work situation at that time. I am busy every day and always walk around. Probably tired, too. I went to work that day and began to have frequent contractions after lunch. I went to the hospital for fetal monitoring and examination. I have opened my finger and it hurts for hours. I was born shortly after I entered the delivery room.

So, don't be too limited to the expected date of delivery. Do a good job in every prenatal examination and listen to the doctor. Prepare the bag in advance, and you must be ready to go to the hospital at any time after the fetus is full-term. Welcome the arrival of the baby with expectation and relaxed attitude.

Very accurate

Not very accurate, the fetus is in the belly, and no one can say for sure.

The expected date of delivery can remind you of the time range of your baby's safe birth, but don't look at the expected date of delivery so accurately. According to the statistics of some scientists, only about 50% pregnant mothers give birth in the expected date.

Pregnant mommy should be ready to give birth at any time after 37 weeks of pregnancy, but don't worry too much. Let it be. If there is no sign of delivery in 4 1 week of pregnancy, you should be hospitalized in time for observation or induced labor.