Calculate the due date by the day of conception. Calculate due date by last monthly. Obstetric method, other methods
Once you find out that you are pregnant, you are overwhelmed with incredible joy. The first time you go and just give everyone your happiness. Over time, when the term becomes a little longer and the first euphoria passes, you can't wait to find out when your baby will be born. You want to plan your childbirth, at least knowing approximately when that day will come, so that you are ready for anything. Today we will show you how to calculate your due date.
Pregnancy is always a joy
Due Date Calculator
Calculation of the due date
How to calculate due date by conception date?
To be completely honest, everyone wants to know the due date. There are two ways:
- The first and most correct option, at least according to doctors, is counting, which is focused on conception.
Everything is very simple here: you need to approximately remember when the sexual intercourse occurred, after which the pregnancy occurred, and add 9 months to this day. The main thing is to calculate everything correctly. If you cannot remember such details, there is another method, which is also associated with the day of conception. - Medical counting.
Every woman knows approximately when her critical days should begin. Based on this information, you can determine how long each cycle lasts. That is, you need to know how many days your period lasts. After that, you can roughly find out what day ovulation occurs. In this case, it is very easy to calculate the date of birth by ovulation. It is believed that it occurs in the middle of the cycle, on days 13-15. Based on these data, you can determine the date of birth.
How else can you calculate your due date?
There is another method that is popular with doctors. With this method, calculating the due date is not as difficult as many people think. Initially, you need to decide what kind of cycle you have. After that, you must remember when the last critical days were. The calculation should be based on when the last period was. In medicine, the first day of your period will already be considered your baby's possible birthday. The estimated date will be calculated from the weeks, which are also called the medical weeks of pregnancy. What is the difference?
Everything is very simple. If in ordinary life we are accustomed to the fact that pregnancy lasts exactly 9 months, that is, approximately 36 weeks, then according to medical standards, this period is 4 weeks longer. In simple terms, the pregnancy will last 40 weeks. The estimated due date is calculated from the critical days plus 40 weeks. It is quite easy to calculate all this. Should not get confused.
The estimated due date determined in this way is considered not entirely reliable, and doctors do not rely on it.
You just need to know your cycle and know when is the last day of your period. The preliminary due date is very easy to calculate. There is a special calculator that will help make the calculation fast. Of course, the sex of the child cannot be calculated using this method.
There is also a table for determining the date of birth. You can also find it on the Internet. In addition to such tables, you can usually find tables for determining the sex of the child. They are usually also based on personal data (menstruation, ovulation). A special calculator will help you quickly calculate your cycle, and you will know when your baby is approximately due.
The easiest way to figure out when your baby is due is to go for a regular ultrasound. It is believed that this is the most reliable way. There, the calculation is based on the stage of fetal development.
As soon as a woman finds out that she is pregnant, her life changes instantly. Someone perceives this news with unconditional joy, others - with surprise and confusion. But absolutely everyone needs to know when the baby will be born. There are quite a few ways to calculate that lucky day. The most famous, commonly used and affordable is to calculate the date of birth by monthly, the calculator allows you to do this automatically. To find out when the baby will be born, you must enter the number when the last menstruation came.
Specify the date of the first day of the last menstrual cycle (period):
How accurate is this calculation? The only answer that can be given is more or less. After all, pregnancy is an extremely individual process. Each child develops according to its own laws. However, the deviation of the calculator by, say, a week is permissible. But if childbirth does not occur even after 10 or 14 days from the planned date, then such a pregnancy is called post-term. Significant anticipation of events is also a pathology. And so, about when childbirth is the norm, what means premature and late birth, and how to calculate their term in different ways - we will talk in this article.
Calculation of the term of delivery by menstruation
It is easiest to calculate the date of birth by menstruation. No additional equipment, complex calculations, or attention to sensations are needed. The approximate date can be calculated by a calculator, as well as by simple independent calculations. To the number in which the last menstruation began, you need to add 7 days, and then subtract 3 months. So, for example, menstruation began on September 1, 2016. Adding a week, we get September 8th. Subtract three months, change the year to the next, and the estimated date of the happy event is June 8th.
A common question is why such a starting point? After all, conception happened later (or earlier), where does the menstrual bleeding have to do with it? From this date, the so-called obstetric gestational age is considered. The stage in the life of the egg is taken into account from the moment it begins to develop until maturation (ovulation). According to this method, the process of waiting for a child lasts 10 months, 40 weeks, or 280 days. This is two weeks more than when calculating the time of birth of a baby by conception.
This technique is used by all obstetricians-gynecologists. Despite its relativity, it is as accurate and convenient as possible for orientation. It is at her that they look back in the first place when the pregnancy is delayed or, on the contrary, seeks to resolve earlier.
You can calculate the cherished day at any moment of waiting for the child. The main thing is for a woman to remember when her last menstruation before pregnancy began.
Other methods of calculation
How to calculate your due date? The answer is quite simple - by all known methods. In the birth chart of each woman, the estimated number of the birth of her baby is indicated, determined by several methods. Reliable (except for the "menstrual" way) include:
- by ovulation;
- for ultrasound diagnostics;
- by registering the first stir;
- by objective examination.
Determination by ovulation
Calculating your due date by your period is as easy as calculating your ovulation. Only in this case, not the first day of bleeding is taken as the main starting point, but the middle of the cycle. If a woman lives on a cycle of 28 days, respectively, the countdown starts from 14 days. The baby will be born in approximately 38 weeks.
But again, the question arises: what to do if the "same" sexual intercourse did not occur on the day of egg maturation? Is it possible then to calculate the date of birth by ovulation?
Yes. The thing is that sperm cells, getting into a woman's body, "wait for the right moment." If the sperm has been injected before this very moment, then the germ cells will wait. They are able to survive in the conditions of the female body for 2 to 4 days (on average). But if the seminal fluid has entered the vagina after ovulation, then pregnancy probably will not occur. It is on such calculations that the calendar method of contraception is based.
However, life cannot be ordered when to emerge and when not. There are cases when sperm survived for a week! It happens that pregnancy occurs during menstrual bleeding (the child is born, of course, by Chuck Norris. Therefore, this technique also cannot claim to be exclusively truthful, although in most cases it works. Most often, the estimated day of delivery is calculated based on ovulation only once, At the initial examination Later, the exact date of egg maturation is forgotten, and there is a risk of error.
Definition by ultrasound
It should be noted that a specialist in ultrasound diagnostics cannot reliably determine the duration of pregnancy. Nonsense? Not really. The fact is that the doctor can only state a fact: the development of the fetus corresponds, for example, to the 20th week of pregnancy. Later, this conclusion is compared with the estimated time, calculated in other ways. It is concluded whether there is a lag in the development of the fetus, whether it is possible to diagnose a frozen pregnancy, or everything is in order.
Accordingly, it is also impossible to calculate the date of birth by ultrasound. The exception is early dates. In the period up to 3-3.5 months, all embryos develop in the same way, they have no individual characteristics (if we are talking about the norm). Only later, some begin to grow faster, adopting the constitutional properties of their parents, while others - more slowly. That is why in the first weeks of pregnancy, the term of its end with the help of an ultrasound machine can be set quite accurately.
Objective definition by a doctor
An experienced obstetrician-gynecologist can predict when a woman will give birth. At the beginning of the consultation, he determines the approximate period of monthly, and then conducts an external examination. The pregnant uterus increases in size every week, grows, reaching certain external landmarks. These include primarily the pubis and navel. Contrary to common logic, the bottom of the uterus is not below, but above. Imagine an inverted pouch or a normally oriented semi-inflated balloon. The uterus reaches the named "reference points" with its bottom. It is well felt through the skin and abdominal muscles, especially in fragile girls.
Already from the end of 3 months, you can determine the height of the fundus of the uterus. At first, it is hidden behind the pubis, by 14 weeks it protrudes from the bosom, tending to the navel, and reaches the middle of the distance at 16 weeks. Exactly under the navel, it is located within 6 months (24 weeks), increasing more and more.
The accuracy of this technique is difficult to assess. On the one hand, the patterns of change in the size of the uterus are the same for everyone. On the other hand, firstly, each doctor has his own hands, and he feels them differently than another doctor. Secondly, the extent to which the uterus is stretched depends largely on the size of the fetus. And it can differ significantly from woman to woman. It should also be noted that at later stages of pregnancy, such a determination is difficult due to the significant elongation of the organ and the high variability in the size of the fetuses.
Definition by first stirring
Each woman can independently calculate the date of birth on a monthly basis. And this does not require, as already mentioned, special attention to your body - it is enough to accurately keep the menstrual calendar. But a method that suggests calculating the approximate time of delivery, focusing on the sensation of movement, asks for a careful attitude to your sensations.
It is believed that with the first movement of the fetus in the womb, the strength of the bond between mother and child is one hundred times stronger. Women finally realize that there is a new life inside them. In this regard, in most cases, great importance is attached to the very first movement of the fetus.
Normally, the baby begins to move as early as 3 months. However, he is still too small for my mother to feel his movements. True, sometimes, I must say, suspicious ladies confuse the processes of digestion with the movements of the crumbs. But a woman really begins to feel the "presence" of her baby at 20 weeks, if she gives birth for the first time, or at 18, which refers to multiparous. It is from this time on in the generic exchange card at each visit of the woman to the consultation, it is indicated whether she feels the movements of the fetus.
- 20 weeks if the firstborn is expected;
- 22 weeks if the woman has more children.
Thus, in the early stages, the estimated number of an important event is best determined by ovulation or using an ultrasound scan. In the second trimester, the doctor will be the best to cope with this task during the examination. But by the second half of pregnancy, you need to listen to the baby's movements.
Calculation of the date of delivery after IVF
In vitro fertilization refers to assisted reproductive technologies. To carry out this procedure, the steam is cooked for a very long time. A man and a woman must pass a lot of tests, cure all somatic ("non-sexual") pathology, lead a correct lifestyle. In addition, a woman's ovaries are stimulated with hormonal therapy before the egg collection procedure.
Doctors are not guided by menstruation, they "set" their own cycle. At the same time, not one or two, but a dozen eggs mature. This procedure is called controlled ovulation. This means that its date is known exactly, because provoked by medication. In this case, it is most correct to consider the moment of the appearance of a new person precisely from ovulation. The date of embryo replanting is known for certain. Usually, pregnancy occurs 12-14 days after the transplant procedure. Thus, the calculation can be carried out from this day.
The fact is that there are no peculiarities of the baby's waiting period in this case. The only difference is that such pregnancies are most often multiple, therefore they are resolved a little earlier.
Date calculation with irregular cycle
In this case, this method of calculating the cherished day is not suitable. You can try to determine by the date of ovulation - the average duration of the menstrual cycle for the year is taken as a basis, and the time for the maturation of the egg is calculated from it. However, even this answer is quite far from the truth. Therefore, a combination of different options is considered the best way - focusing on ultrasound and the approximate gestational age.
But if the cycle is regular, but lasts more than 28 days, then difficulties should not arise. Ovulation, one way or another, occurs in the middle of it, so the "X-day" is simply calculated, and further calculations are carried out on it.
When is the normal time?
Urgent labor is a delivery that occurs between 37 and 41 (40 weeks and 3 days) weeks of pregnancy. Moreover, in obstetric practice, the main method is the calculation of the monthly. The term "urgent" is used in this case not in the understanding of "urgent, urgent", but as a delivery that occurred "on time."
This means that a healthy full-term full-term baby can be born at both 37.5 and 39.5 weeks. And no one, not a single person, calculator or apparatus is able to guess or know how long it will take to mature completely. That is why absolutely all calculation methods are arbitrary and imprecise.
Shortening or lengthening the waiting period for a crumb is almost always a deviation from the norm. Exceptions:
- hereditary predisposition (deviation can be in any direction);
- multiple pregnancy (labor starts earlier).
Premature birth
About 35% of babies are born before term. For some of them, early birth is irrelevant. However, children who see the world too early often have serious health problems, need resuscitation and then special care.
Childbirth is distinguished very early (22-27 weeks), early (28-33 weeks), actually premature (34-36 weeks). In Russia, a baby is considered a live birth if it is born later than 22 weeks, weighing more than 500 g, with a body length of more than 25 cm and having one of the following signs:
- breath;
- palpitations;
- pulsation of the umbilical cord;
- muscle contractions.
Premature birth may be due to:
- stress;
- stimulation of labor (intercourse, climbing stairs, taking Oxytocin);
- pathology of the cervix, including cervical insufficiency;
- inflammatory process;
- high water;
- past abortions and miscarriages;
- and etc.
It happens that when trying to calculate the date of birth by monthly, an error occurred. The baby, born at 36 weeks, actually grew and developed already 38. The dominant role is not played by the date that was originally set. The judgment about the urgency or premature delivery is based on the baby's condition.
Postterm pregnancy
If the baby is not born on the 3rd day of the 41st week, then the pregnancy is considered delayed. This condition is more favorable than prematurity, because all organs and systems are already developed to the required state. However, the longer the baby is in the uterus, the larger its size, the more traumatic childbirth will be for a woman. In addition, long-term presence of the fetus in the uterus helps to reduce the intensity of uteroplacental blood flow, causing oxygen starvation in the fetus.
The reasons for the late completion of the process of bearing a child may be:
- dysfunction of the placenta;
- endocrine pathology in mom;
- large fruit;
- wrong psychological attitude, fear of childbirth.
Thus, there are many options for knowing when to expect your baby to arrive. You can calculate the date of birth by monthly, the calculator will help you, you can use any other described method. The most important thing is to carefully monitor your body, avoid stress, breakdown of the regime, and also carefully prepare for pregnancy. Then the process of waiting for the baby will be easy, and the birth will come on time.
Special preparation is needed for this day. There is so much to buy, cook, study a huge amount of literature, think over all possible scenarios for the development of events. And we, women, think that it would be a shame not to take into account something.
All pregnancy is not only a spiritual attitude, but also quite material chores that should be carefully planned.
In a simple formula due date calculations the main component is the gestational age. Conception occurs most often on the days of ovulation, but not every woman knows when these very days come.
It's simple - exactly in the middle of the menstrual cycle, i.e. after 12-16 days from the first day of the last menstruation.
For example, your last period began on April 1, which means that the egg will go on its difficult path on April 12-16.
This calculation of due date is suitable for women with an average menstrual cycle of 24-28 days. With deviations from day to day in one direction or another, the timing of ovulation also changes.
Let's assume that conception took place in the middle of the last menstrual cycle, from which time the long 40 weeks of your pregnancy begin.
Trying to calculate the due date by week
Some women mistakenly add 9 months and get an "estimated" secret date. This is not true, since pregnancy lasts a little longer - approximately 280 days or 40 weeks.
True, the doctor quickly eliminates this error and helps the patient to determine with the help of a special calendar that any gynecologist has.
This calendar has the easiest counting system - from the first day of the last menstruation you need to subtract 3 months (April 1 minus 3 months = January 1), then you need to add 7 days to the resulting date (1 + 7 = 8), the result obtained is the estimated period childbirth, which your gynecologist will enter on the card.
The second method of calculation is to add 280 days to the first day of the menstrual cycle.
But you cannot focus only on these calculation systems, because for some, a full-term pregnancy can last 38 weeks, and for others - 42, all this is within normal limits.
Multiple pregnancies, as a rule, end earlier than the date calculated by the doctor.
How to correctly calculate the term of labor by perturbations. Folk omens
To determine the due date, you can use the folk omen, which for many centuries, even before the development of medicine, helped expectant mothers.
Exactly in the middle of pregnancy, primiparous women first feel the movements of their baby - this significant event usually occurs in the 20th week.
Multiparous mothers identify tremors as early as 18 weeks. the walls of the uterus after childbirth become thinner, and therefore more sensitive, therefore, in the second / third / fourth time, intrauterine movements are perceived better.
By the time the intrauterine movements begin, you need to add 20 and 22 weeks for the first and subsequent pregnancies, respectively.
But this method is not very accurate either, because girls with different complexions feel jolts at different weeks, a thin woman feels movements within herself already at 15-16 weeks, and a denser woman at 21-22 weeks.
It is worth adding that not all expectant mothers can immediately correctly assess the incomprehensible movements within themselves - some confuse this action with an intestinal disorder, sorry, or the movement of the abdominal muscles (weak convulsion).
You can also determine the approaching birth already in the last trimester - by dropping the tummy. This process makes pregnant women feel a little better and takes place 2-4 weeks before delivery.
We calculate the term of delivery by ultrasound
Another method for assessing the due date is computer diagnostics, or, more simply, ultrasound. In the early stages (up to 12 weeks), ultrasound can determine the day of conception with an accuracy of the day, based on the size of the head and trunk of the embryo.
Until a certain point (about 3-4 months of pregnancy), all babies develop in the same way, after which the genetic predisposition, dietary habits and lifestyle of the mother are already affected.
Ultrasound examination in the second and third trimesters will have an error of up to 2-3 weeks, because babies are different and the weight of newborns can range from 3 to 5 kilograms.
Inexperienced gynecologists can take the date calculated by the computer as a basis, and after the "estimated 40 weeks", begin to take unnecessary measures in connection with the "post-term" pregnancy.
Finally, a gynecological examination on a chair can be considered almost as accurate as an ultrasound scan.
An experienced doctor by the size and shape of the uterus will be able to determine the gestational age by touch, based on which further calculations will be made, which we determined at the beginning of the article.
It should be borne in mind that you cannot rely one hundred percent on any of the listed methods, they are approximate and give a result that can vary by 2 weeks in one direction or another. You should focus on your feelings and nature, which is never wrong.
Calculation of the due date
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Calculation of the due date
Pregnancy is the most desired and long-awaited event for any woman. Therefore, there is nothing surprising in the fact that long before the documentary confirmation (two cherished stripes on the test) of an "interesting" situation, each of us already feels changes in the body.
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After your gynecologist diagnoses "pregnancy" and determines the exact date of conception, it will take only 280 days or 10 obstetric months until the fetus is fully ripe. At the same time, one should not clearly focus on these indicators. They are very individual and depend on the physiological characteristics of a particular woman and on the environment in which she carried the child. It is known from practice that only 4% of babies are born clearly after 280 days. The rest, due to various factors, may be born earlier or later. In order to find out the approximate date of birth of your baby and determine the so-called gestational age, they are guided by the first day of the last menstruation.More calculators:
Do you have any more questions? read the answers below:
1. How accurate is the calculation for the day of conception
To understand the accuracy of the calculation, you need to decide on the calculation method. It's no secret that conception is possible only during the period of ovulation, during which a mature egg is released from the ovary. The duration of the menstrual cycle is an individual feature of every woman. On average, it can be from 28 to 35 days.
Ovulation occurs in the very middle of the menstrual cycle. The exact date can be determined by ultrasound, using special home tests for ovulation, or by measuring basal temperature. Some women have special signs on this day, by which she can determine that today is ovulation. It is on this day that conception occurs, which may not coincide with the day of physical intimacy, since sperm cells are able to maintain their viability in a woman's body for a week.
Knowing the day of conception, it is also a tribute to ovulation, it is quite easy to calculate the date of birth: you just need to add 266 days. This will be the estimated due date. The accuracy of these calculations will directly depend on the accuracy of determining the date of ovulation. If your cycle is not constant, and you are not sure about the date of conception, then this technique may give some error.
2. How to calculate the date of birth by menstruation
This method of calculating the expected date of birth is used in antenatal clinics. It is also called obstetric term. To determine the expected date of birth, you need to know the date of the start of the last menstrual period. This day is the starting point for the calculation. If the duration of the menstrual cycle is 28 days, then you can use the Negele formula, according to which the date of birth is calculated as follows: from the day of the beginning of the last menstruation, three months are subtracted and seven days are added. You can also use another technique: 280 days are added to the date on which the first day of the last menstruation fell. According to scientific data, it is this period that is necessary for the ripening of the fetus.
But if your cycle is longer or irregular, then it will not be entirely correct to calculate the date of birth by menstruation. If the duration of the menstrual chicle exceeds 28 days, then labor is likely to come later, if on the contrary, then earlier. If the cycle is not regular, then this method of determining the expected date of birth will be rather indicative and cannot be used as a basic technique.
3. How to calculate the date of birth by the first stir
Often, to determine the expected date of birth, they use such a landmark as the very first movement of the baby inside the abdomen, more precisely, the moment when the mother was able to feel the movement of her baby. Therefore, it is also called intuitive and experts consider it inaccurate. Moreover, if a woman gives birth for the first time, then she will most likely feel the first movement in the twentieth week of pregnancy. If a woman is about to have a second birth, and she already knows what exactly she should feel, then the first movement of the fetus in most cases is felt at the eighteenth week. Now, in order to calculate the date of birth according to the first stirring, if the pregnancy is the first, it is necessary to count exactly 20 weeks from the date of the first stirring. If a second birth is coming, then only 18 weeks need to be counted.
As practice shows, quite often many primiparas and women giving birth again begin to feel the movement of their baby already at a period of 15-16 weeks. But there are also mothers who felt the first movement of their baby only at the period of 21-22 weeks.
Do not rush to apply this technique in practice to determine the expected date of birth, since in fact it is not known which category of expectant mothers you belong to.
4. How to calculate the date of birth by ultrasound
The most accurate method for determining the date of birth is considered to be diagnostics by ultrasound (by ultrasound), but it must be used very early, no later than the twelfth week. This method allows you to diagnose the gestational age with an accuracy of one day, thus indicating the approximate date of conception and, accordingly, the date of birth.
Later, the gestational age is determined by the size of the baby's head and limbs. But this conclusion does not allow us to accurately diagnose the expected date of birth, since each child develops completely individually, having a different weight not only at the moment of birth, but also during the period of its intrauterine development. Therefore, when determining the date of birth in the second trimester, an error of up to seven days appears, and an ultrasound scan in the third semester hardly makes it possible to judge the duration of pregnancy, based on the intrauterine dimensions of the baby.
Thus, in order to accurately calculate the date of birth by ultrasound, it is necessary to undergo an examination during the first three months of pregnancy. Otherwise, the intrauterine size of the baby will not allow you to accurately determine the date of the expected birth.
The duration of pregnancy from conception to childbirth is about 266 days, or 38 weeks. Since the date of conception is usually not known for sure, in modern obstetrics it is customary to calculate the gestational age from the first day of the last menstruation. With this calculation, it is approximately 280 days, or 40 weeks, since ovulation (the release of a mature egg from the ovaries) and, accordingly, fertilization usually occurs about two weeks after the onset of menstruation. When turning to an obstetrician-gynecologist, many expectant mothers begin to worry about the difference in the date of birth - the one that the doctor calculated and the alleged woman herself. In order not to worry in vain, you need to know that there are two stages of pregnancy - obstetric and embryonic.
Fetal term- this is the true gestational age from conception, it usually lags behind obstetric by about 2 weeks.
Obstetric term doctors determine from the first day of the last menstruation before pregnancy. It should be remembered that all doctors use it: the size of the fetus, the timing of examinations, maternity leave and the date of birth are calculated taking into account only the obstetric gestational age. The exact period of pregnancy is also very important to know for screening tests for genetic abnormalities in the fetus (ultrasound and blood tests), since these examinations are carried out at strictly defined periods of pregnancy.
During the first visits to the antenatal clinic, the obstetrician-gynecologist usually determines the estimated date of birth (PDD). There are several ways to do this.
Method 1. The method of determining the date of birth by the date of the last menstruation
This is the most common way to calculate the DA. Subtract three months from the start date of your last period to calculate your due date. You need to add 7 days to the resulting date - this number is the very expected date of birth. Obstetricians-gynecologists, when calculating the PDR by this method, usually use special obstetric calendars, which greatly simplify the calculations.
However, it is far from always possible to accurately calculate the PDR using this method alone. This happens when a woman has irregular periods, or those patients who have a regular but long menstrual cycle. For example, if a woman has a typical cycle duration of 35 days (and not 26-28, like most), then most likely, she will be able to conceive only on about the 21st day of the cycle (and not on the 14th, as with a 28-day cycle). Accordingly, your period-based PDE will be one week earlier than your actual estimated due date.
Method 2. ovulation date or conception date
If the date of conception is reliably known, then you can calculate the estimated date of birth yourself, adding 266 days - this is the average gestation period. But here, too, there are some nuances. You need to understand that even if a woman knows exactly the date of ovulation or the date of sexual intercourse after which the pregnancy occurred, this does not mean that she absolutely knows the date of conception. A sperm that has entered the female body is capable of fertilization on average for 4–5 days, sometimes even within a week, and a mature egg retains the ability to conceive for 2 days after ovulation. Therefore, even knowing the exact date of sexual intercourse or ovulation, it cannot be said with certainty that fertilization took place on that particular day. It could have happened later. Therefore, the term calculated by ovulation or the date of conception cannot be considered absolutely accurate.
Method 3. Method of determining the due dateon the first visit to the antenatal clinic
Usually, the date of the upcoming birth and the gestational age are calculated by the doctor when registering for pregnancy. Doctors call this method of calculation - according to the "first attendance at the antenatal clinic." The duration of pregnancy, and, accordingly, the date of delivery in this case is determined by the following parameters - the size of the uterus and the level of chorionic gonadotropin in the blood. Examining a woman in a gynecological chair, an obstetrician-gynecologist with both hands determines the size of the uterus. This method works most accurately in the early stages of pregnancy, up to about 12 weeks. The earliest term that can be determined by the size of the uterus is 5 weeks of pregnancy. By this time, the uterus enlarges slightly, softens and becomes rounded. At a later date, the size of the uterus may vary slightly depending on the size of the fetus, the amount of amniotic fluid, and the structure of the woman's pelvis.
A blood test for hCG (human chorionic gonadotropin) helps to determine the duration of pregnancy and calculate the approximate date of birth in the early stages. It begins to be produced in the body of the expectant mother with the onset of pregnancy, and gradually, until about the 11th week of pregnancy, its amount increases and then decreases slightly. Determining the concentration of hCG in the blood at the beginning of pregnancy helps to accurately determine its duration. Having received the results of a blood test for hCG, it is worth paying attention to the fact that the embryonic period is often indicated in the laboratory tables, which determine the correspondence of the hormone level to the gestational age. That is, to determine the usual obstetric gestational age, 2 weeks should be added to the result obtained.
Method 4. The method of determining the date of birth n about ultrasound
When conducting an ultrasound scan in early pregnancy, by measuring the size of the ovum and embryo, the gestational age can be determined with great accuracy. At 4-5 weeks in the uterus during ultrasound examination, a small "black circle" is determined - this is a fertilized egg, in which an embryo will appear a little later. At about 6-7 weeks, an embryo appears in the form of a small "strip", and you can see its heartbeat. More accurate is the period calculated by measuring the CTE of the embryo (CTE is the coccygeal-parietal size, that is, the maximum distance from the head of the fetus to its coccyx). After 12 weeks, the gestational age with ultrasound is determined by measuring various sizes of the fetus's head and abdomen, the length of its arms, legs, etc.
Up to 9-10 weeks of pregnancy, the embryo grows proportionally, and its size in all women with the same gestational age will be approximately identical. In the future, these indicators will differ in expectant mothers of different nationalities, with different body weights, the weight of the mother and father at birth will also matter, and so on. That is, in the later stages of pregnancy, normally developing babies of the same "age" can have different sizes (fluctuations can be about 2 weeks and sometimes even more), and in such a situation, it is impossible to reliably determine the gestational age according to ultrasound data.
Method 5. The method of determining the date of birth nabout the first stirring of the fetus
We note right away that this method for determining the PDD has been used less and less recently. It is based on the fact that women who are carrying their first child begin to feel its first movements on average at about 20 weeks of pregnancy, and pregnant women for the second or more times, a little earlier, at 18 weeks. That is why obstetricians-gynecologists recommend that the expectant mother remember the date of the first fetal movement and enter these data into the exchange card. To calculate the expected date of birth in women preparing to become a mother for the first time, 20 weeks must be added to the date of the first fetal movement, and for those expecting a second baby - 22 weeks.
However, this method of determining the date of the upcoming birth is often mistaken. What is the matter here? The problem is that the time when a woman can feel the first movements of the fetus is very individual and depends on her sensitivity, physique, as well as on employment and experience. So, some expectant mothers feel the first movements as early as 15-16 weeks, and some only after 20. Slender women, as a rule, begin to feel them earlier than full ones. Expectant mothers who lead an active lifestyle, who work a lot, usually feel the fetal movement later than those who are less busy and have more opportunity to listen to their inner feelings. Pregnant women for the second or more times already know exactly how the baby's movements are felt, therefore, as a rule, they recognize the baby's movements earlier than “inexperienced” primiparous women, who often mistake fetal movements for increased intestinal motility and gas.
All of the above methods allow you to calculate the expected date of delivery. However, it must be remembered that, of course, it is not completely accurate. Overweight or undermaturity of pregnancy is not uncommon. Abnormalities in fetal development, pathological processes in the body of the expectant mother, stressful situations, hereditary factors and many other reasons can provoke the onset of premature labor. Therefore, it is very important to realize that calculating the date of birth is a very conditional concept, regardless of the method used, and it is not possible to predict exactly when the baby will be born.
How is the estimated due date of IVF calculated?
In the case of IVF (in vitro fertilization), fertilization of an egg with a sperm is performed "in vitro" by an embryologist. Embryos develop in the laboratory for 3-5 days, after which they are transferred to the uterus. Doctors calculate the true gestational age after IVF from the date of ovarian puncture, that is, procedures when the follicular fluid and the follicles contained in it are taken with a special needle for subsequent fertilization "in a test tube", and to determine the "usual" obstetric period, add 2 weeks by the date of ovarian puncture.
If the transfer of the embryo into the uterus was preceded by its cryopreservation (that is, freezing in liquid nitrogen), to determine the exact duration of pregnancy, doctors add 5 days to the transfer date (this is the number of days of embryo development before freezing), and to determine the obstetric period, add 2 weeks, and the due date is calculated.