Terms of pregnancy: obstetric and fetal -how to determine and not get confused in terms

Once for each future mother comes the very, special
day. She learns about her new condition. And soon the woman often
будет слышать вопрос: «Какой у вас (у тебя) срок?» Как
to calculate the duration of pregnancy to answer correctly?

The content of the article

  • 1 Obstetric term
  • 2 Fetal (true) term – from conception
  • 3 Can there be difficulties?
  • 4 How else to determine the date?
    • 4.1 Gynecological examination
    • 4.2 ultrasound
    • 4.3 The baby is pushing!
    • 4.4 When weeks are centimeters
  • 5 And when will be born?

Как определить срок беременности

It’s pretty simple!

Almost always the answer to the question about the duration of pregnancy will be based
on the two most famous and popular counting techniques –
obstetric and fetal (from conception) terms

Obstetric term

The beginning of pregnancy is the first day of the last menstruation.
This method is called obstetric. It does not take into account individual
features of the woman’s body, but is almost universal. Them
will be used by any doctor.

The obstetric method has its own logic. Calculation of the term goes with
the earliest stage of pregnancy – the beginning of maturation

Using the obstetric method, the doctor will determine the expected date of birth.
(DA), as well as the period of maternity leave. In medicine taken
assume that the pregnancy lasts 280 days. This well-known 40
weeks or 10 lunar months.

Why 10 months, not 9? And why are the moon months? �“Blame”
this is astronomy. The moon repeats its phases at intervals of 28
days (4 weeks). This is the lunar month. And if you count in
calendar months, then their normal pregnancy is really
fits only 9.

Fetal (true) term – from conception

Beginning of pregnancy – the first day of the last menstrual period plus 2
of the week. It is believed that in the middle of the cycle ovulation occurs.
In this case, the period from one period to the other takes the average – 28

This method of calculating the term is called embryonic or true.
But it is worth considering: is the truth hiding somewhere else? WITH
medically, ovulation can occur between 12-18
days from the start of the cycle.

Example. Oksana’s husband from the beginning of spring to
Late autumn constantly went on business trips. Sometimes I was at home
one or two days a month. Shortly after another visit of her husband
Oksana realized that she was pregnant. And with a smile, she thought she knew the exact
Conception date is 2 June. After all, before and after this day, she and her husband
виделись почти по две of the week. Oksana’s last periods were
May 18-21. And if to consider May 22 the beginning of the cycle, then the conception
состоялось на двенадцатый day. And the egg was already ripe.
Or not?

Another question is important here – how long is ovulation
is going on? If strictly according to science, then a few seconds. After all
ovulation is only the release of a ripe egg from the follicle. But
most of us consider ovulation and the next few (or
even a lot of hours, which the egg will live in the female body.
WITHколько? Sometimes up to two days. By the way, about the same will live
in the female body and sperm after intercourse. And sometimes
дольше – до of the week.

So the true day of conception is a real mystery! After all вполне
There may be two different situations. Ovum moves to uterus
the second day and literally at the end of his life is
fertilized. Or vice versa. WITHперматозоиды попали в организм
женщины до овуляции и фактически «дождались» выхода ovum.

As accurately as possible the day of conception is known to couples who carefully
planned pregnancy. In this case, the day of ovulation is determined
using a special test (sold in a pharmacy) or by ultrasound.

тест на овуляцию

There is another old method for determining ovulation. This measurement
basal temperature. It is held in the morning, in the same
time to rise from the bed (even the eyes are recommended not to open).
The thermometer is placed in the mouth, vagina or rectum.
Before ovulation, the basal temperature drops slightly, and then
is increasing. Это и означает выход созревшей ovum.

And sometimes women themselves feel that ovulation has come. Bottom
belly aches a bit, vaginal discharge gets a little more
viscous. And the attraction to the beloved man becomes stronger.

That is why many expectant mothers consider their gestational age.
by the embryonic method: the beginning of the cycle plus 2 weeks or
known to them the day of ovulation. In this case we are talking about the term from

Can there be difficulties?

Ludmila’s periods often came literally “through time”.
The doctor’s verdict is ovarian dysfunction. While Luda did not live sexual
life, not too worried. But after marriage often
came the same question. Delay is a manifestation
dysfunction? Or contraception did not work? Once the second option
turned out to be true. But подсчитать срок обычным методом врачи не могли
– there was a clear discrepancy.


The former athlete Valeria first monthly came only in
16 years. And the cycle was not installed. Between critical days
could take up to six months. She did not go to the doctor. Somehow
did not find time – then study, then personal life. Once thin
Valeria noticed that she clearly recovered. The first reaction is
desire to go on a strict diet and remember the old sports
loads. It is good that at first the girl consulted with her
mom More precisely, with the future grandmother of her child.



Lena’s firstborn just turned ten months old. Kid
grew up healthy, and the nursing mother decided on the occasion of such a round date
eat melon. A few hours after that, she felt sick.
Lena thought she was poisoned. But вскоре врачи прояснили ситуацию:
Lena was pregnant again. The first menstruation after childbirth is simply not
had time to start.

WITHколько ещё подобных случаев! If a woman has a period
go irregularly or did not have time to come at all, as in the situation with
Lena, traditional calculations will not help. Well, that is
alternative methods.

How else to determine the date?

If the obstetric term is not counted, the doctors will
use other methods of counting. There are several:

  • on the basis of a gynecological examination;
  • using ultrasound;
  • on the first stirring of the fetus;
  • according to the size of the uterus.

In some cases, the doctor “looks after” all the signs
less to be wrong in calculating the term.

Gynecological examination

An experienced gynecologist can only calculate the size of the uterus.
right term The hands of the doctor accurately determine the boundaries of the uterine cavity.
Если матка по размеру сравнима с куриным яйцом, срок – 4 of the week. BUT
if closer to goose, then we are talking about eight weeks.

This method works effectively if the gestation period is less than 12


Ultrasound scanning nowadays effectively
examine the fetus and even make some measurements. In the first
trimester, the doctor will determine the size of the ovum and compare it with
traditional data. In the second and third, the doctor will measure
circumference of the chest, tummy or head. Last “measure”
considered the most accurate to determine the date.

In the first weeks of pregnancy, calculating the term in this way
gives a very accurate result. Later, future babies start hard
be different: someone is bigger, someone is smaller. WITHовсем как в жизни,
which is waiting for them in the future.

Kid толкается!

The first movement of the fetus – another indicator. If a woman
preparing to give birth to her first child, she will feel his movements at 20
weeks. If the baby is second, third and so on, then the first
шевеление ожидается в 18 weeks. These are official medical
data. And future babies do not think that they should
Be sure to follow!

The fetus actually makes its first movements in the first
trimester of pregnancy. But будущий ребёнок ещё такой крошечный, что
Mom still feels nothing for many weeks. But бывают и

Inna was waiting for the second child. And so was thin, and in the first
weeks have lost weight. With a height of 167 cm – 46 kg. And this is in the second
trimester! The doctor shook her head disapprovingly and worried. BUT Инна
felt great. Nausea almost did not torment, vomiting was
occasionally. True, always wanted oranges, and one red
�”Handsome” always lay in the bag. In general, no problems
It was.

Kid толкнулся на семнадцатой неделе. WITHначала один раз, а
after a couple of hours – one more time. And the next day, and the day
the woman felt the same way. At the next reception at the gynecologist
Inna called the date. The doctor shook her head again, smiled
and clarified – maybe it was the gases? Inna laughed – movement
baby she remembered well even in the first pregnancy and make a mistake
just could not.

True, sometimes all the same can be confused. If the expectant mother
regularly suffers from flatulence, and even the child is waiting for the first time,
the movement of gas through the intestines is sometimes taken by her for stirring

When weeks are centimeters

And another way that is related to the size of the uterus. More precisely, with her
high. This method is available only to doctors. Pregnant woman
lies on the couch. The doctor takes a centimeter tape or special
instrument – tasomer. Determines the upper and lower boundaries of the uterine
cavity and makes measurements.

The height of the uterus in centimeters – this is the gestational age. Thats
if the doctor intends 30 cm, then the gestation period is 30

These four methods (usually in combination with each other) give
the most accurate determination of the duration of pregnancy.

BUT когда родится?

Estimated birth date will prompt mom when baby appears
to the light. But это теория. Children very rarely follow the calculations of doctors.
True, exceptions are here.

На Ultrasound в 12 недель Лике назвали ПДР – 10 марта. Lika only
shrugged her shoulders slightly. WITHвоего первого малыша она переносила ровно
a week The doctors then said that the baby probably wants more
grow up And it is true that even the worn son weighed at birth.
only 2 kg 700 g

Therefore, early in the morning of March 10, Lika did not even immediately understand that
contractions began, and persistently tried to sleep a little more. But не
happened. Soon it became clear – it began. That’s so daughter and
born – exactly prechnochno in time.

Formula Negele:

Quite accurately, the expectant mother can calculate the DA herself. Of course,
if the monthly periods before conception were regular.

  1. It is necessary to add to the first day of the last menstruation seven
    days, and then take three months.
  2. Или к первому дню последней менструации прибавить 9
    месяцев и 7 days

Here is the approximate date of birth of the future crumbs!

You can learn the DA, using a special calendar.
pregnancy for the last month. В красной строке ищем дату
the beginning of the last menstruation, next to her, in the yellow line,
видим дату вероятного дня родов.

таблица предполагаемых родов

таблица предполагаемых родов

Например, последние месячные начались 28 января. Плюс seven дней
– This is the 4th of February. Minus three months – get the 4th of November. And how is it
will actually – life will show.

The main thing is that at any stage of pregnancy was

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