The doctor in the LCD says about some obstetric weeks of pregnancy, the ultrasound sets a completely different period, and according to your calculations, the third is obtained. And how can an inexperienced future mommy not get confused here. In fact, everything is not so difficult, you just need to deal with some of the nuances.
What is an obstetric term and why is it needed?
Obstetric weeks of pregnancy include the period from the first day of the last pre-pregnancy menstrual period to the expected due date (PDD). The obstetric period is 280 days or 40 weeks, or 10 obstetric months (a month is 28 days). The obstetric weeks of pregnancy are counted even when conception has not yet occurred, but the processes of maturation and release of the egg have passed successfully.
The definition of obstetric weeks is necessary for the convenience of calculating the timing of pregnancy. After all, no doctor can say for sure when a woman had ovulation and, accordingly, conception. And the woman herself can, of course, guess about the possible day of conception, but not be completely sure of it. Meanwhile, as the date of the beginning of the last menstruation is remembered by almost all the fair sex.
What is embryonic term and ultrasound term of pregnancy?Fetal term is the life span of your baby, first as an embryo, and then as a fetus. The embryonic period lasts approximately 265-266 days (38 weeks or 9 normal months).
Ultrasound examination determines the estimated duration of pregnancy based on the available size of the baby, while relying on the standard indicators of its development at embryonic (up to 12 weeks) and obstetric (after 12) weeks. The ultrasound timeline is rather imprecise. The size of the fetus, like the size of an adult, is individual, small children are born, heroic children are born, a slight deviation (no more than 2 weeks from the norm for the corresponding week of pregnancy) is allowed. Nevertheless, the definition is very important, a significant deviation from the standard indicators indicates various pathologies in the development of the baby.
How to count obstetric weeks of pregnancy?
The doctor should tell the expectant mother what the obstetric weeks of pregnancy are and how they are considered. But if suddenly he did not cope with his task, and you forgot to clarify this point with him yourself, the following information is for you.
So how do you calculate your obstetric pregnancy weeks? It's pretty simple. Take the calendar, remember the date of the first day of the last menstruation, count from this day (inclusively with it) the number of days or weeks (as you like) to today, you get. If you counted in days, do not forget to divide the resulting number by seven. If you want to know the date of the expected birth, use the same scheme to calculate 280 days. You can determine the PDR in a different way, namely: according to the same calendar, count three months from the first day of the last menstruation back and add 7 days.
How are obstetric weeks and fetal weeks different?Based on the above, the difference between obstetric and fetal weeks of pregnancy is in the order in which they are counted. Obstetric term 
is 280 days (count from the last menstruation). Meanwhile, embryonic lasts approximately 265 days (count from the day of conception).
If a woman's menstrual cycle was regular and stable, then with a high percentage of probability it can be assumed that ovulation occurred in the middle of the cycle and in the middle of the cycle, respectively, conception occurred. That is, the difference in time between obstetric weeks of pregnancy and embryonic in a healthy woman with a regular menstrual cycle lasting 28-30 days is within two weeks. In women with an irregular cycle, the embryonic period can only be guessed at.
During the bearing of the first baby, a woman faces many questions. Most of them are related to how she should be feeling, and how to react to certain changes in her body. But in addition, many expectant mothers are faced with the problem of determining the exact duration of pregnancy. And the numbers given in the results of ultrasound and gynecological examination may differ. Usually, when calculating, doctors use the obstetric gestational age, but in some cases the real term can also be used, let's try to figure out which calculation is right for you? And how to correctly calculate the gestational age?
In most cases, it is not possible to determine the exact date of conception, which is why, to understand the duration of pregnancy, doctors have always focused on the date when the last menstruation began. This method of calculating the gestational age is called obstetric. However, such calculations have nothing to do with the date of conception, because a new life arises much later.
As you know, pregnancy occurs at the moment when the egg is fused with the sperm inside the fallopian tube. In most cases, such an event occurs exactly on the day of ovulation or within a day after its completion. Thus, calculating the gestational age from the moment of ovulation, it is possible to more or less accurately determine the actual period of fetal development.
However, this technique is far from always suitable for further monitoring of the course of pregnancy, since in many women ovulation does not always occur exactly in the middle of the cycle. In absolutely healthy women, this event can happen a little ahead of schedule or, on the contrary, a little later. Therefore, the real (embryonic) gestational age is often simply impossible to determine.
The obstetric period began to be calculated a long time ago, when there was no information about the features of the course of pregnancy, as well as about ovulation. Many years ago, the only symptom of the onset of conception for a woman was the absence of menstruation, therefore, the period was counted from the moment of the last menstruation.
Obstetric gestational age and real calculation - the difference
A typical menstrual cycle lasts four weeks - twenty-eight days. In this case, conception falls somewhere on the fourteenth day, just at this time ovulation is maximum possible. Accordingly, the actual period of development of the fetus and obstetric will differ by about two weeks.
Accordingly, if the doctor tells you about the gestational age of four weeks, then the real age of the embryo is only two weeks.
However, depending on individual characteristics, such a difference may be greater or smaller.
If the length of your menstrual cycle is slightly different from the standard, most likely fertilization occurred a little earlier or later than the fourteenth day of the cycle. Accordingly, the actual gestational age will be slightly different than when calculated by the date of the last menstruation.
For example, if the average cycle length is not twenty-eight, but thirty-five days, then conception can occur only on the twenty-first day of the cycle, and not on the fourteenth. Accordingly, in the first week of the delay, the real period will be the third week, and by the date of the last menstruation it will be already the sixth week.
When trying to correctly calculate the duration of pregnancy, you should not focus solely on the date of intercourse. As practice shows, sperm can remain active in the female genital tract for up to five days, waiting for the maturation of the egg and the completion of fertilization.
How else can you determine the term?
In the very first weeks after conception, for the most accurate determination of the gestational age, you can take an analysis for hCG. The results obtained will make it possible to determine the most accurate age of the fetus.
To determine the term at a later stage of gestation, you can sign up for an ultrasound scan. Until the twelfth week of gestation, such a study extremely accurately shows the age of the baby, since its development occurs approximately the same in all women. In this case, the doctor can write as a result both the true (real) age of the fetus and the obstetric gestational age. Accordingly, it is imperative to check with the specialist conducting the research what exactly he means.
How is the gestational age determined during a routine gynecological examination?
A qualified gynecologist, conducting a vaginal examination of a patient, can detect pregnancy at the earliest stages of development, from about the third to fourth week. But of course, the terms he named cannot be called 100% accurate.
How does cycle length affect overall pregnancy?
In fact, it makes no difference how long your monthly cycle lasts. On average, about nine months pass from the onset of conception to the date of birth, but this period may deviate in one direction or another, depending on the individual characteristics of the woman, as well as on her from the course of a particular pregnancy.
Conclusion
We talked with you about the difference between real and obstetric pregnancy. Correct determination of the gestational age, taking into account the length of the cycle and the approximate timing of ovulation, helps to calculate the approximate date of birth as accurately as possible. That is why it is extremely important to inform your doctor about all the features of your body.
Pregnancy is the most enjoyable event in the life of any woman. Have you noticed how a young lady flourishes during this period? She becomes brighter, more sincere and open. Waiting for a miracle, a woman can worry and worry, which is quite normal and is due to hormonal changes in her body. One of the reasons for concern is worries about the timing of pregnancy. Today we will try to figure out what is the difference between obstetric weeks and ordinary weeks.
Obstetric weeks and regular weeks
When calculating the gestational age, the concepts of obstetric week and obstetric month are used. The obstetric week, like the usual one, consists of seven days. The midwife month consists of four weeks.
How are obstetric weeks calculated?
Several methods of calculating the gestational age are used to determine the due date. Among them, there are embryonic, obstetric terms and the term, which is established according to the data of ultrasound examination of the uterus. A normal pregnancy lasts nine months. This is the embryonic period, which is thirty-six weeks from conception or nine obstetric months. In obstetric practice, the concept of "obstetric weeks" is also used. Few people know about this, so it will be useful to clarify what the obstetric gestational age is and how it can be calculated.
Obstetric weeks of pregnancy are normally forty weeks, which equals two hundred and eighty days or ten months, with one month being twenty-eight days. To calculate the gestational age, add one week to nine months and you will get the approximate due date. Obstetric weeks are counted from the first day of the last menstrual period to the onset of pregnancy. This method of counting has long been used by our ancestors. Normally, every girl and woman has a period once a month, which lasts for 3 to 5 days. If menstruation occurs regularly, the woman knows she is not pregnant. Obstetric weeks can be calculated only in those women who have already established a menstrual cycle, and menstruation begins at regular intervals.
TheDifference.ru determined that the difference between obstetric weeks and regular weeks is as follows:
- The obstetric week is used to calculate the gestational age, the usual week is used to calculate the calendar dates.
- Four obstetric weeks are equal to an obstetric month. With calendar weeks, the situation is completely different - here each month does not have a certain number of weeks.
Pregnancy is one of the most beautiful periods in the life of the fair sex. It is worth noting that medicine knows two options for calculating the time of bearing a fetus in the uterus: obstetric gestational age and real.
Where does it all start?
To begin with, it is worth talking about how fertilization occurs. Around the middle of the month, the female egg leaves the follicle and slowly moves along. It is here that it meets the male cell. Next, the chromosomes merge, and conception occurs. Having descended into the uterine muscle, the ovum is introduced into the endometrium, and from that moment it can be considered that the pregnancy has taken place.
Determining the duration of pregnancy
When a woman realizes that she is in an interesting position, her initial task is to determine the date. The gestational age is calculated by week. Usually the time span during which the baby is in the mother's womb is 40 weeks. A slight shift in one direction or another is considered normal and does not require any correction. Doctors distinguish between obstetric and real pregnancy.
Real time of carrying a baby
This period starts from the moment when ovulation occurs. The release of the egg from the follicle is the day from which the actual gestational age is calculated. Most women's clinics that monitor the course of pregnancy use this particular calculation method. If you decide to take a blood test to determine its content, then you will also be provided with a result that indicates the real value of the period.
Obstetric gestational age
This time period begins its countdown from the first day of the last spotting from the genital tract of a woman. To calculate the estimated date of birth of a baby, this is the term used. Also, many of the fair sex use this method in order to establish the period of pregnancy. That is why so often women have discrepancies with the calculation made by the doctor.
Obstetric gestational age and real
In most cases, the difference between these counting methods is two weeks. With a standard female cycle of twenty-eight days, the release of an egg from the ovary occurs exactly two weeks after the start of the last menstruation.
However, not all women have a standard cycle length. For example, some women ovulate one week after the start of their last period. In such cases, the difference between obstetric and real terms will be one week.
If a woman's egg release occurred three weeks after the start of the last menstruation, then in this case the obstetric gestational age and the real one will have a difference of twenty-one days.
All situations described are normal. That is why the duration of pregnancy by week should be set taking into account the length of the woman's menstrual cycle. It is impossible to equate all the fair sex under generally accepted standards. This can lead to an incorrect calculation of the period of bearing the baby.
pregnancy by ultrasound
There are situations when a woman cannot name the date of the first day of her last period. This situation often occurs if a woman has recently given birth or is breastfeeding. In such cases, the fair sex is recommended to undergo diagnostics with an ultrasound machine (ultrasound).
A short period of pregnancy, which is not yet possible to establish with a manual examination, is easily diagnosed by ultrasound. It is worth noting that a specialist can determine the presence of a woman in the uterus starting from the fourth obstetric week. All measurements and definitions of the term are calculated in this obstetric way.
Instead of a conclusion
If you are unsure of how to calculate your pregnancy, ask your doctor. In most cases, it is enough to know the date of the last menstruation and the length of the woman's menstrual cycle. If necessary, an ultrasound examination is also prescribed. Carry out the calculation using the same method used by a specialist. Only in this case, you will not encounter discrepancies and will not get into a controversial situation.
As you know, in most cases, it is quite difficult for young girls to establish the exact date of conception. That is why in medical practice, when establishing the period of pregnancy, they always started from the date of the beginning of the last menstruation preceding pregnancy. With this calculation, the so-called "obstetric" gestational age is established, which is slightly larger and differs from the real one.
How is obstetric pregnancy calculated?Many women who become pregnant for the first time do not know what the obstetric gestational age means and how to determine it. With a normal duration of the menstrual cycle (28 days), conception is possible by about 14 days. Due to the fact that the date of the last menstruation is used when calculating, then usually the obstetric and embryonic (real) periods of pregnancy do not coincide. The break between them is those same 2 weeks, and sometimes even 3.
How to calculate the embryonic (real) gestational age?
In order for a pregnant woman to independently calculate the actual gestational age, it is necessary to know the exact date of conception. If you cannot install it, then modern ones can come to the rescue. The design of such devices is based on electronic sensors that allow you to accurately determine the duration of pregnancy. In this case, the error is small.
The situation is much simpler when a woman remembers the exact date of her last sexual intercourse. In this case, it is only necessary to calculate how many days have passed since that moment. The resulting number of weeks will be the real gestational age.
How to correctly calculate the duration of your pregnancy?According to statistics, the difference between the real and obstetric period of 2 weeks is observed in only 20% of pregnant women. Another 20% have a gap between these two periods of less than 14 days. For the majority, 45%, the difference between the 2 terms fluctuates in the interval of 2-3 weeks, and only in 15% of pregnant women it is more than 3 weeks.
If the average duration of a woman's menstrual cycle differs from the standard 28 days, then fertilization does not occur on day 14, but a little earlier or later. Therefore, the embryonic period will differ sharply from that determined by the gynecologist.
For example, if a woman's cycle lasts 35 days, then conception can occur only at 21 days, and not as usual, at 14. Therefore, the embryonic gestation period at 1 week of delay will be 5 weeks. Moreover, if you count from the last menstruation, then it will already be 6 weeks.
What if you can't determine the deadline yourself?In the early stages of pregnancy, it is possible to determine the period quite accurately only with the help of an analysis for. With its help, the approximate age of the fetus is established. In this case, the calculation is carried out from the date of the alleged conception. More accurately allows you to set the time of ultrasound. When conducting this study, the sizes of individual parts of the fetus are taken into account, according to which its age is established. Based on the results of the ultrasound scan, it is possible to establish how the obstetric period of pregnancy, 
and embryonic.
When determining the gestational age, the cycle length can also be taken into account. Indeed, with a longer menstrual cycle, conception occurs a little later, therefore, childbirth will occur later.
Thus, knowing the main differences between obstetric and embryonic gestational age, women will share these 2 concepts, and not be surprised that the period set by the gynecologist is longer than her anticipated, which is calculated according to the date of conception.
