Calculating the expected date of birth (EDD) can be done in several ways, and each of them will only be indicative. Every gynecologist has a “favorite” method that he relies on. But the deviation of the due date from the calculated one is a variant of the norm.
The proposed method is on the first day of the last menstruation. Suitable for women with a regular cycle lasting 28 days.
How to use the calculator
Just enter in the field the date of the first day of the last menstruation - and press the button “Find out the due date”.
How else can you find out the gestational age and date of birth
1. In the first trimester, you can find out the gestational age with high accuracy directly at an appointment with a gynecologist. He will determine the period without any tests, simply by the size of the uterus. In the 2nd and 3rd trimesters, this will no longer work.
To make calculations in this way, you need to add 280 days to the date of ovulation.
You can use the date of sexual intercourse as the initial data (just keep in mind that fertilization of the egg can occur on the 2nd or even 3rd day after it.
3. Hardware calculation of gestational age and date of birth using ultrasound. By this method, the period can be determined with an accuracy of 1-3 days.
Using ultrasound, a specialist can observe the condition of the fetus, placenta, the position of the child’s head in relation to the entrance to the pelvis, the size of the opening of the cervix and other important parameters. That is why this method is highly accurate.
The question of how to determine the due date often causes discussion and controversy among pregnant women. The difference between your own calculations, the deadlines that are set during an ultrasound examination and those that the doctor writes on your card is completely confusing. Specifically, in order to make life at least a little easier for pregnant women, we have developed a program that independently calculates the approximate date of birth. Now you don’t have to visit a doctor or bother yourself with mathematical calculations; in order to calculate the date of birth of your baby, you just need to enter the number when your last menstruation began in the required column of the calculator.
Naegele's formula is a two-step problem.
The program that allows you to calculate the date of birth is based on the Naegele formula, named after the German obstetrician who first proposed using this simple method of calculation. It is known that pregnancy lasts on average 40 weeks from the beginning of the last menstruation or 38 from the moment of conception. Nägele simplified the calculations by reducing them to a few simple arithmetic operations - remember the date of the onset of menstruation preceding pregnancy and subtract 3 months. You need to add 7 days to the resulting figure - this number is the very date of birth.
The question often arises: why should the date of birth be calculated based on the date of the last menstruation? This tradition, generally accepted in obstetrics, is justified, because not all women know exactly the day of ovulation, while the majority keep a menstrual calendar. It is also natural to be bewildered - after all, in the first, so-called “weeks of pregnancy,” conception has not even occurred yet. Yes, this is true, and this period refers to the period of pregnancy conditionally, for the convenience of obstetricians and gynecologists, according to standards. The fetus begins to exist when about 14 days of pregnancy are already behind. If you reliably know the date when fertilization occurred, you can calculate the date of birth yourself by adding 266 days - this is the average gestation period.
Is deviation from the estimated date normal?
It is worth noting that the expected due date is nothing more than a guideline for you. In fact, about 17% of women give birth on day X, the remaining 83% a little earlier or later. No specialist can predict the onset of labor. Moreover, normal, term births, that is, births that occurred within physiological periods, are considered to be those that occurred from 38 to 42 weeks of pregnancy. Unpredictable miscarriage or miscarriage of pregnancy often occurs. The onset of premature labor can be triggered by abnormalities in fetal development, pathological processes in the maternal body, stressful situations, hereditary factors and many other reasons. Therefore, it is very important to understand that calculating the due date is a very conditional concept, regardless of the method used
However, there is a certain pattern, taking into account which we can assume the development of the situation during a healthy pregnancy - the longer the monthly cycle, the longer the pregnancy lasts. Before you determine your due date, taking into account your individual characteristics, remember the duration of your menstrual cycle - from the first day of some periods to the first day of others. If the cycle is longer than the standard 28 days, the pregnancy will probably last more than 40 weeks, and vice versa. Keep in mind that we are talking about postponing the estimated date of birth by no more than 5 days.
The calculator will help you calculate the date of birth based on your period as accurately as possible, but you should remember that the data obtained during a medical examination is crucial, as it is more reliable. The reason for this approach is that menstruation can easily be confused with bleeding that began after conception and stopped spontaneously. Also, during an examination in the third trimester or an ultrasound of the uterus, the doctor can observe the degree of maturity of the placenta, the position of the fetal head in relation to the entrance to the pelvis, the opening of the cervix, signs of full-term fetus and many other important data. Based on all these parameters, one can judge the readiness of the fetus and uterus for labor and the likelihood of its imminent onset. In addition, focusing on the size and proportions of the fetus during ultrasound examination, the doctor determines the age of the fetus in accordance with.
Analyzes and examinations
Registration at the antenatal clinic. First appointment with a gynecologist
at 5-8 weeks of pregnancy
The doctor will conduct an examination, confirm the fact of pregnancy and draw up your individual examination plan. During the examination on the chair, the doctor will clarify not only the fact of pregnancy, but also the condition of the uterine appendages, and will also take all the necessary smears for infections and the epithelium from the cervix for oncocytology (examination for the presence of cells that can cause cancer). The gynecologist will collect data about your health, ask about your relatives’ diseases, and clarify the features of your lifestyle. The doctor will give you a considerable stack of papers - directions for subsequent tests.
Blood test for hCG (human chorionic gonadotropin)
at 5-8 weeks of pregnancy
The presence of pregnancy is determined by the level of hCG and the stability of its development is assessed. If necessary, the doctor can prescribe this test again to clarify the dynamics of the growth of this hormone, which can be used to judge how correctly the pregnancy is developing at this stage.
First ultrasound
at 5-8 weeks of pregnancy
The study will allow you to clarify the duration of pregnancy, see if everything is okay with the fertilized egg, and sometimes even see the heartbeat of the embryo.
Colposcopy
at 5-8 weeks of pregnancy
Special examination of the cervix using a microscope.
Primary laboratory diagnosis
at 8-10 weeks of pregnancy
General urine analysis will help evaluate the functioning of the kidneys and bladder (urinary system).
Vaginal flora smear will show the presence of possible inflammatory processes in the pelvic organs, hidden and obvious infections.
Examination for urogenital infection. The infection is sexually transmitted and is fraught with serious consequences for the health of the expectant mother and fetus.
General blood analysis which you take in the morning on an empty stomach will help assess the condition of your body. It reflects the blood’s ability to carry oxygen, the presence or absence of an inflammatory reaction, and the body’s ability to stop bleeding. This analysis is basic; deviations in it are the basis and starting point for a more detailed examination.
Blood for AIDS, syphilis, hepatitis B and C– this is the identification of antibodies to serious infections, each of which has a significant impact on the health of the pregnant woman and the fetus. If an active process is detected, the question may even arise about the advisability of continuing the pregnancy.
Determination of Rh factor and blood group must be done once, at the very beginning of pregnancy. If you are diagnosed with a negative Rh factor, you need the future dad to also undergo a similar test. If the child’s father is Rh positive, it will be necessary to monitor Rh antibodies in the pregnant woman’s blood throughout the pregnancy, as they can greatly harm the child. Today, technology even makes it possible to determine the Rh factor of the fetus by its DNA in the mother’s blood long before birth.
Blood test for TORCH infection will indicate to the doctor the presence or absence of toxoplasma, mycoplasma, cytomegalovirus and herpes virus in your body. The doctor, if necessary, will select the right treatment.
Coagulogram will help determine the main parameters of the blood coagulation system, identify the tendency to bleeding and thrombosis.
Determining the level of glucose in the blood will show the gynecologist how efficiently your pancreas works and whether glucose tolerance is impaired in the pregnant woman’s body.
Feces for worm eggs.
Blood test for hormones(TSH, T4, AT to TPO, AT (antibodies) to TG) - in order to find out the state of your thyroid gland. You may need additional medication support.
Blood chemistry will help determine the condition of internal organs - kidneys, liver, pancreas.
Blood test for antiphospholipid antibodies- for accurate diagnosis of diseases of the immune system. Prescribed if there is a history of pregnancy loss.
Visiting doctors
at 8-10 weeks of pregnancy
It is necessary to visit a therapist, dentist, otolaryngologist, ophthalmologist, surgeon, cardiologist, endocrinologist.
Electrocardiogram
at 8-10 weeks of pregnancy
It will allow you to clarify the absence or presence of problems in the work of the most important muscle in the body, the load on which increases many times over from the moment of pregnancy. If abnormalities are detected on the ECG, the therapist will prescribe an ECHO-CG, which allows you to more accurately determine the degree of cardiac dysfunction.
General urine analysis
at 10 weeks of pregnancy
Dynamic monitoring of a general urine test will allow you to evaluate the functioning of the kidneys and bladder.
First trimester screening
at 12 weeks of pregnancy
A screening study for chromosomal abnormalities and gross malformations of the fetus consists of several procedures:
- Ultrasound, by which the doctor can assess whether the fetus has visually gross developmental pathology, as well as the presence or absence of signs that may indicate any genetic disease (Down syndrome, Edwards syndrome);
- A blood test showing whether certain indicators are abnormal, which may also indicate the risk of systemic genetic diseases.
- computer analysis of the degree of individual risk of having a child with a chromosomal abnormality in this couple, taking into account the results obtained from ultrasound and biochemical research.
- vaginal examination, assessment of the condition of the cervix. This is one of the periods in which ICI can begin to form (isthmic-cervical insufficiency, when the muscles of the cervix weaken earlier than required). Therefore, the gynecologist needs to examine you and assess the size and consistency of the cervix. If during the examination ICI is indeed detected, depending on the situation, the doctor will either monitor the condition of the cervix over time or suggest hospitalization.
If the delay in menstruation is slight and there are no complaints about poor health, then there is no need to rush to an appointment at the antenatal clinic yet. But your inner feeling already tells you that a miracle has happened and that you will soon become happy parents of a wonderful baby. Any woman in this position strives to get an answer to the question: when exactly is the time for childbirth? Our service allows you to determine the exact date of birth of your unborn child in a matter of minutes.
Calculate due date online
Any method of calculating the date of expected birth is based on an idea of the normal duration of pregnancy, which usually lasts about forty weeks (in some cases, a deviation of several weeks is also not a pathology). The starting point is the beginning of the last menstrual period, and it is likely that the expected event will occur after exactly 280 days or 40 obstetric weeks.
Using the online calculator presented on the website, you can easily and simply find out the likely date of your upcoming birth. All that is required of you is to enter the necessary data into the appropriate windows of the calculator, and the necessary calculations are performed by the computer. The principle of the calculation is very simple: the date of the start of the last menstrual bleeding and the traditional 280 calendar days are summed up.
The date obtained is approximate and corresponds to ideal medical indications. The actual timing may vary slightly depending on the individual characteristics of the woman, her state of health and the general course of pregnancy.
Pregnancy calendar, how to calculate the date of birth by menstruation
Find the date of your last period on the blue line of the calendar. The date that is under it (red or yellow) will be the date of birth.
Calculate due date by date of conception
Not every woman knows exactly the day when conception occurred, so doctors cannot reliably determine the so-called “embryonic” gestational age. However, if the time of fertilization is known, then the results of calculating the time of birth will be much more accurate, because each child needs the same period for full intrauterine development. In such cases, you need to add 280 days again, this time to the date of conception.
When calculating the date of birth based on the day of fertilization, minor errors are allowed, because pregnancy could have occurred on a different day than the corresponding sexual intercourse. Research shows that conditions in the vagina are quite favorable for sperm, so they can stay here for several days before merging with the egg. The error ranges from one to three days, but no more. Thus, the date of conception determined by this method is also approximate.
Calculate due date based on ovulation
You can determine the date of birth of a baby by calculating the day of ovulation. This method is not suitable for everyone, because only a small number of women carefully monitor their menstrual cycle and, even more so, keep an ovulation calendar. If at least the approximate date of ovulation is known (with a constant cycle of 28 days, it falls in the middle), you can get a more or less accurate date of birth. To do this, you need to add 280 days to the ovulation date.
Of course, the most accurate results can be obtained if you have the maximum amount of initial data. The best option seems to be a combination of all the presented methods for calculating the date of birth. But in any case, waiting a few days is not a big problem, because the main thing is the birth of a healthy child and subsequent pleasant troubles.
Video: How to determine the due date.
Knowing the exact due date is important for every pregnant woman, because it is better to go to the maternity hospital in advance, on your own, and not at the emergency room. Today we will figure out why all children are born at different times and how to determine your gestational age.
The timing of childbirth depends on various reasons: is there a norm?
Gynecologists claim that there is no standard period for normal childbirth - there are conditional frameworks. Normal delivery can be at 37 and 44 weeks. It is generally typical for twins to be born at 36-37 weeks, and women with a long monthly cycle have every chance of giving birth after 42 weeks.
You need to understand that if a child was born normally developed at any stage, this is the norm. In case of deviations in development and health due to the timing of birth, children are divided into premature and post-term.
- Babies with low weight, height, and poor development of organs and body are called premature. Their mothers carried them for less than 37 weeks - until the 260th day of pregnancy, so the babies were not able to achieve the required parameters. According to statistics, 20% of children are born prematurely.
- Post-term babies are born after 42-44 weeks - during the period 294-308 days of pregnancy. Do not think that when you overwear you will have a giant. On the contrary, there are signs of a post-term baby: thinness, dry, wrinkled skin, weak muscles. The reason for this condition is the aging and death of the placenta, through which nutrients were supplied. Approximately 10% of mothers walk.
From the foregoing, it follows that it is better to give birth at a period of 37-42 weeks. Knowing exactly when this moment should come, it is easy to navigate during premature contractions or when you are postmaturity.
Will doctors help if the due date is shifted?
Of course yes! If you notice signs of impending premature birth, you can contact a gynecologist and he will take action. If there is a threat of premature birth, bed rest and various medications are prescribed to relieve contractions and relax the uterus.
In case of postmaturity, at 40 obstetric weeks of pregnancy, the expectant mother is placed in the maternity hospital for observation. Examinations and stimulation with a drug that causes contractions speed up the process. If necessary, the doctor can open the amniotic sac, after which labor either begins or a cesarean section is performed. After the water breaks, the baby will appear no later than 12 hours later.
If the due date has nevertheless moved forward, do not despair, now both significantly premature babies and “slightly” post-term babies are being cared for. The most dangerous condition is significant postmaturity of the fetus - the baby may be born dead or with serious pathologies - every second post-term baby shows signs of suffocation, hemolytic jaundice, damage to areas of the brain caused by oxygen starvation, etc.
How to calculate due date in gynecology
The obstetric gestational age begins on the first day of your last period. It sounds a little strange, since at this time there is no child yet, but it is more convenient for doctors. In addition, pregnancy dates begin to be counted from the day of conception, which is usually considered the day of ovulation. Normally, ovulation occurs two weeks after the first day of the last menstruation.
This is where the calculation problems start. there may be two in a month, it may move in the opposite direction. and ovulation can specifically occur due to classic stress, taking certain medications, inflammation in the reproductive organs, and other reasons. For some women, conception is delayed and can happen right on the “safe” day - just before menstruation. For others, menstruation, on the contrary, can continue even after pregnancy. In these cases, it will be more difficult to determine the timing.
Initially, the gynecologist sets the period based on a survey of the patient and data from a gynecological examination. By palpating the uterus, the doctor determines its size, which corresponds to the period of pregnancy. The estimated duration of pregnancy, for example 6-7 weeks, is recorded on the card; this indicator serves as the starting point for calculating the date of birth.
Formula for calculating due date
You can calculate the preliminary date of birth (the due date is abbreviated as PDD) using a simple formula. It is also used by obstetricians.
To calculate pregnancy, the date of the first day of the last menstruation is taken as the basis. Childbirth should take place after 40 obstetric weeks, which is. 280 days.
Formula for calculating the day of birth: From the first day of the last menstruation, subtract 3 months, add 7 days to the result.
Example: The last period began on September 5th, counting back 3 months, we get June 5th. Adding 7 days, we get the DA on June 12.
Online due date calculator: you can find out when to give birth right now
- Estimated date of conception.
- Timing of important stages in the development of pregnancy.
- Current gestational age.
- Due date (date) of birth.
- Newborn zodiac sign.
It is worth understanding that this method cannot guarantee an accurate result, because an online calculator is just a set of formulas designed for a standard situation. Therefore, it is possible to find out the due date in this way only approximately.
How to determine the term of childbirth accurately - ultrasound of the fetus and no amateur performance!
The most reliable method for determining the due date is an ultrasound examination of the fetus, called pregnancy screening. The ultrasound specialist, based on the readings of the device, compares the size of the fetus with the standard and makes a verdict - the gestational age and the date of the PDR (preliminary date of birth). Or rather, this way you can very accurately determine the gestational age, and the date of birth will be estimated, since, as we noted above, it depends on many factors.
It is not for nothing that there is a proverb among pregnant women: “PDR was invented by the enemy,” since the coincidence of birth with the date set by the specialist does not always happen.
Causes of premature and delayed birth:
- Body parameters of a pregnant woman. The state of health, structure and condition of the uterus.
- Hormonal balance(labor activity begins under the influence of a hormone that stimulates uterine contractions).
- Fetal parameters. Development depends on the quality of blood supply, genetic characteristics, location, etc.
- Presence of dangerous infections. A number of infectious diseases can cause premature birth.
- Injuries, stress and other factors.
Symptoms of violation of the timing of childbirth
It’s quite easy to understand that something is wrong; the following symptoms correspond to premature birth:
- Premature birth begins with aching in the abdomen, the appearance of discharge, and increased fetal activity. The stomach may not hurt - there will be a slight "sipping" in the back. Water may break - a large amount of liquid will flow out. All these signs are 3 reasons to call an ambulance.
- With true overbearing, the stomach and weight decrease. Milk may appear in the breast instead of colostrum. And with an ultrasound, doctors will determine whether the baby is suffering from lack of nutrition or whether you simply have a prolonged pregnancy.
If you have had a premature birth, there is no need to panic. If the child breathes on his own and his weight is more than 2.5 kg, then everything is in order. A little love, care and mother's milk, and he will grow up to be a great person. There are many such examples in history. For example, Napoleon Bonaparte was born two months prematurely.
But if you collected all the birth packages at 37 weeks, and are already 42, then immediately go to the maternity hospital. You should not hope for a doctor’s mistake - if the due date was set on an ultrasound of the fetus, then you need to trust him.
Where to determine the date of birth in St. Petersburg?
There is a specialized one in St. Petersburg. There is a new ultrasound machine with Doppler, which also allows 4D formats. Reception is conducted by leading obstetrician-gynecologists with the highest qualification category. Prices for fetal screening are minimal, from 2 thousand rubles. - only 1000 rubles. Here you can also get tested for hCG and TORCH complex.