What is the difference between obstetric weeks from ordinary calendar weeks? How to calculate the term of pregnancy: Methods

What is the difference between obstetric weeks from ordinary, calendar? Details in the article.

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A woman may not immediately guess that she will soon become a mother when the body does not give any signals. But, if there is a delay in menstruation, morning nausea, sensitivity to smells, then you should make a test or make an appointment with a doctor.

Read on our website another article on the topic: "Stress during pregnancy". You will learn about the reasons if the child feels stress in the womb, how dangerous he is for the mother and baby.

Not all women know that there are obstetric and ordinary, embryonic weeks of conception. From this article you will find out what is the difference. Read further.

Why do you need to know the gestational age?

If a woman wants to endure and give birth to a healthy baby, knowing the gestational age is simply necessary. The expectant mother goes to the doctor and is registered in the antenatal clinic, where the map necessary for the hospital is issued. It will indicate the term of pregnancy established by the gynecologist Date of childbirth, all tests and examinations of specialists.

It is worth knowing: A visit to a doctor is recommended for a period of no later than 12 weeks.

The advantages of surveillance from the early term:

Diagnosis will help to identify possible diseases in a pregnant woman, to conduct, if required, treatment and solve the issue of preserving pregnancy.
This allows you to set an exact period, to predict possible complications of pregnancy. Draw up an observation plan.
At a period of 12 weeks, the woman goes to conduct an ultrasound and biochemical screening of the first trimester. This is required to diagnose possible disorders in the development of the fetus, congenital malformations associated with chromosomal pathology.

As you can see, you need to go to the doctor in a timely manner. This is necessary for the health of the future mother and identifying any diseases at an early date, if any.

How to calculate the term of pregnancy: Methods

The gestational age is set using two main methods:

Embryonic term:

This method is used if the date of conception is known.
A woman can calculate the term herself, but the result will not be accurate enough.
Ovulation occurs in the middle of the menstrual cycle. This is 14-15 days after the start of the last menstruation. Comparing with the date of sexual intercourse, you can establish a day of possible conception.
But, keeping such an account, only the approximate date turns out, since after ovulation the egg lives several days, maintaining its ability to fertilize. And the sperm that has entered the woman’s body is able to do this not on the day of sexual intercourse, but over the next 4-5 days.

Obstetric Dates:

The countdown goes from the date of the first day of the past menstruation, after which the pregnancy occurred.
It is this date that the doctor asks for the term of pregnancy in the card when registering.
This method is used for a regular cycle in a woman who lasts 28-30 days.
If the monthly cycle is irregular and its duration is from 30 to 35 days, the embryonic date of the date of conception is used.

There are several more ways:

It is possible to determine at a period of 5 to 12 weeks when examining a gynecologist by a doctor by uterine size.
Ultrasound study - "ultrasound", It can set a more accurate period if the pregnancy is presumably no more than 10 weeks. Until this moment, all embryos are developing the same way. A fruit egg and embryo are measured on the device. According to these parameters, the deadline is set.
On hCG - "chorionic gonadotropin of man". It is produced by the fetal membrane of the embryo. And already on 6-8 days after conception, you can determine the onset of pregnancy in hCG in the blood.
The most inaccurate method that should not be used is the first stirring of the child. In the first pregnancy, this occurs at 20 weeks, and with subsequent ones - from 18. It is difficult to feel the first movement of the fetus, a more obvious move can be heard a few weeks later.

Relying on your feelings, and is not under the supervision of a doctor and not undergoing examinations until the late pregnancy is fraught with poor consequences. Remember this, and take into account in a timely manner and consult a doctor.

What is the difference between the obstetric week from the usual, embryonic, calendar week of conception?

The difference between the obstetric week and the usual, embryonic

The difference of obstetric and ordinary, embryonic, calendar week of conception is only in the calculation.

We count obstetric weeks:

We take the number of the first day of past monthly, including it.
You can count on the calendar days and weeks before the current date.
If we count by the day, then divide by 7. To find out the estimated date of birth, we count 280 from the initial day.
You can use the opposite method of counting, taking three months from the first day of the last menstruation and adding seven days.

Embryonic weeks:

In total they are 265 days.
The difference with obstetrician is approximately two weeks if the woman’s menstrual cycle is regulatory.
In the absence of the stability of the cycle, the exact embryonic period can only be assumed.

The difference between obstetric and calendar week:

The duration of pregnancy is determined by the obstetric week. It is 7 days. Accordingly, the obstetric month is 4 weeks. We multiply the days by weeks and get 28.
In the calendar week, too, 7 days. But the calendar month has no exact number of weeks, it is enough to carefully look at the calendar.

Summing up, we can say that the obstetric period is 40 weeks or 10 months before the day of childbirth. Although they say that the pregnancy lasts 9 months, amounting to 36 weeks. This is an embryonic period. It can be called real, because it is considered from the moment of conception. Therefore, do not worry and worry if the period set by the doctor is more than the estimated for 2 weeks.