Calculate your due date based on your last period. Due date calculator. Determining the date of birth: What are the ways to determine the approximate date of birth

How to find out the date of birth? About the method of calculating the date of birth

For estimated due date calculation obstetrician-gynecologists have a very convenient and simple formula: 9 months and 7 days are added to the date of the first day of the last menstruation. And you can calculate even easier - from the first day of the last menstruation, count back 3 months and add 7 to the resulting number.

Estimated date of delivery = date of the first day of the last menstruation + 9 months + 7 days.

Estimated date of delivery = date of the first day of the last menstruation - 3 months + 7 days.

But these terms are typical for the average woman with an average 28-day menstrual cycle and ovulation on the 14-15th day of the cycle.

The average pregnancy lasts 266 days (38 weeks) from conception, or 280 days (40 weeks) from the first day of your last period. If the menstrual cycle of the future mother is shorter or longer than the average 28 days, or ovulation did not occur on the 14-15th day of the cycle, then the pregnancy can also be longer or shorter. Therefore, it is generally accepted that 280 days is an approximate number of days of pregnancy and a child can be born between the 266th and 294th day (38–42nd week) of pregnancy.

Calculation of the date of birth by the day of conception is not an accurate method for determining the due date. Even if you know exactly the day when sexual intercourse took place, this does not mean that conception occurred on that day, since spermatozoa are able to remain active in the vagina for up to several days.

How else can you determine the gestational age and calculate the date of birth?

Determining the gestational age with ultrasound

In the early stages, up to 12 weeks of pregnancy, it is possible to calculate the date of birth using ultrasound quite accurately. Over long periods, this is often difficult due to the fact that each child grows at his own pace. Namely, such indicators as the sizes of different parts of the fetal body are the basis for calculating the gestational age.

Determination of the gestational age during a gynecological examination

During pregnancy, the uterus begins to gradually increase in size and takes on a spherical shape. With a gynecological examination up to 12 weeks, the doctor can determine the approximate gestational age by the size of the uterus. For periods of more than 16 weeks, when the uterus extends beyond the womb, you can determine the period by the height of the standing of the bottom of the uterus during examination of the abdomen. Naturally, this method of determining the gestational age is not accurate.

Determination of the gestational age by the first movement of the child

Another auxiliary method for determining the gestational age and calculating the date of birth is by stirring. Despite the fact that the child begins to make movements quite early, the mother can only feel them when the baby reaches a certain weight. This usually happens in nulliparous women at 18-20 weeks of gestation, and in multiparous women 2 weeks earlier. However, some women claim that they feel movements as early as the 14th week and sometimes earlier.

Using all of the above methods, you can more or less accurately determine the gestational age, but the date of birth will still be approximate. This means that the chance of giving birth on the due date +/- 3 days is about 70%. Do not forget that the child's readiness for extrauterine life also affects the date of birth. Some children of the so-called morpho-functional maturity can reach the 38th week, while others - at the 41st.

If the delay in menstruation is small and there are no complaints about feeling unwell, then you should not rush to an appointment at the antenatal clinic. But an inner feeling already tells you that a miracle has happened and soon you will become happy parents of a wonderful baby. Any woman in this position seeks to get an answer to the question: when exactly will the time of birth come? Our service allows you to determine the exact date of birth of the unborn child in a matter of minutes.

Calculate due date online

At the heart of any method of calculating the date of the expected birth is the 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 menstruation, and it is likely that the expected event will take place exactly in 280 days or 40 obstetric weeks.

With the help of the online calculator presented on the site, you can easily and simply find out the probable date of the upcoming birth. All that is required of you is to enter the necessary data in the appropriate calculator windows, and the necessary calculations are made by the computer. The principle of the calculation is very simple: the date of the beginning of the last menstrual bleeding and the traditional 280 calendar days are summed up.

The date obtained is an approximation, corresponding to ideal medical indications. The actual dates 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 below it (in red or yellow) will be the due date.

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 for the day of fertilization, minor errors are allowed, because pregnancy could not have occurred on the day when the corresponding sexual intercourse occurred. Studies show that the conditions in the vagina are quite favorable for sperm cells, so they can stay here for several days before merging with the egg. The error is from one to three days, but no more. Thus, the date of conception determined by this method is also indicative.

Calculate due date by 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, moreover, keep an ovulation calendar. If at least the approximate date of ovulation is known (with a constant cycle of 28 days, it falls in its middle), you can get a more or less accurate date of birth. To do this, add 280 days to the date of ovulation.

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, a few days of waiting is not a big problem, because the main thing is the birth of a healthy child and subsequent pleasant chores.

Video: How to determine the date of birth.

First trimester: 1-13 weeks

At the "start" after conception, an embryo is formed, but the signs are poorly felt by the mother. Details:

1 Week For pregnancy to occur, it is necessary to attach an egg that travels through the tubes to the wall of the uterus. The expectant mother feels the world deeper, becomes more thoughtful. Many women at this stage feel symptoms, as before menstruation - pulling the lower back, aching in the stomach. To determine the gestational age in weeks and calculate the due date from the last menstrual days, use our pregnancy calculator. Try not to drink pills and eat right;
2 weeks- a follicle matures in the ovaries during ovulation, then it bursts, the egg comes out, the breast becomes sensitive, irritability increases slightly, but libido also increases. No saunas and baths during this period! No weight lifting! Only exercising, swimming, not smoking, orange juices and green vegetables rich in folic acid, which helps to absorb iron! Taste habits change, you often want to go to the toilet, pressure decreases;
3 week- the embryo lives in the mother's body, the egg is fertilized by the sperm, divides, after 2.5 weeks it reaches the uterus, which becomes loose by the end of this period. Nothing prevents the egg from attaching securely to the mucous membrane. The metabolism changes, the mammary glands coarsen. It is necessary to replace sweets with nuts, eat foods rich in calcium, protein, folic acid, iron;
4 week- Mom detects a delay in menstruation, nausea, malaise may appear. Hormones released during pregnancy can be seen already in the urine in a laboratory analysis. The internal organs are laid in the embryo, the mother needs vitamins;
5 week- the uterus thickens, the baby looks like a tadpole, but its eyes and nostrils are already forming, there is already a heart, the base of the skeleton is formed. The baby receives nourishment and oxygen from the mother's blood. The woman's ovaries actively release progesterone, the mother's immunity decreases. In 7 days, the embryo grows up to half a centimeter;
6 week- the formation of a fetal bladder is underway, protecting the embryo from any troubles, the nervous and circulatory systems are developing hourly. There are processes of creation of the brain, liver, respiratory organs, pancreas. The baby grows up to 1.3 cm;
7 week- the size of the head of the embryo reaches 0.8 cm. The visual system is formed, the neural tubes thicken, the upper part of the intestine secretes the esophagus, stomach and pharynx, the bladder, rectum are visible under the lower part, in male embryos - the prostate. In a woman, the skin of the face can become oily during this period, as in a teenager. Hormonal changes can cause itching. In case of any trouble, it is better to consult a doctor for advice;
8 week- the nervous system receives maximum development, the medulla oblongata is ready for work, the spinal cord and brain have already fully formed, the eyes are still without eyelids, there is a nose, fingers and elbow joints appear on the handles. Mothers should beware of infections;
9 week- the third month begins, the face acquires human features, the eyelids form, a sucking reflex appears, the circulatory system circulates inside the tiny organism, the heart acquires three chambers, the bronchi branch. Mommy's breasts are growing so much that the next bra number is required. The uterus increases, the ligaments stretch, pulling sensations in the lower abdomen for this period are the norm;
10 week- A 5-centimeter embryo is already considered a fetus, on ultrasound you can see its gender. His nervous system was divided into central and peripheral, the hemispheres of the brain become more independent. An enlarged uterus is groped even with hands, you constantly want to go to the toilet;
11 week- the baby's body gradually straightens, reaches 5.9 cm, the legs begin to actively catch up with the arms, an iris forms near the eyes, lymphocytes appear. The mother's kidneys experience a double load, removing metabolic products for two;
12 week- A 50-gram fetus has grown to more than 7 centimeters, the movement of the chest during breathing is noticeable, the heart beats more than 150 beats per minute, milk teeth, vocal cords, and diaphragm are formed. Mothers need to get enough sleep, exercise, keep calm;
13 week- the placenta has reached 16 mm, becoming a reliable protection for the baby. From this point on, the body will even withstand antibiotics, if necessary. Bones and ribs need calcium. Without subcutaneous fat, the skin looks wrinkled. Mom may experience constipation, lower blood pressure, and disturb the kidneys. It is important to eat right in order to gain no more than 11 kg for the entire pregnancy, for multiple pregnancy - no more than 17 kg;

Second trimester: 14-27 weeks

This is a mildly flowing period of bearing a baby, during which the mother's body is completely ready to work for two, despite weight gain, rounding of shapes, and the appearance of a belly. The embryo has fully formed internal organs and systems, the child moves its limbs, sucks its finger, and the feeling of its movements gives the mother endless delight. More:

14 week- the baby maintains the chemical composition of the amniotic fluid, excreting urine in them up to several times a day. The ovaries in girls and the prostate in boys are improved. The lack of vitamins affects the well-being of the mother. She has a feeling that there is not enough air. It is worth eating less potatoes and legumes. You may be allergic to strawberries, peaches, oranges;
15 week- the heart of the crumbs overtakes about 23 liters of blood, convolutions form in the brain, the bone marrow develops, the intestines form the original feces, the amount of amniotic fluid increases. You can talk to your baby! The height of the uterus reaches 14 cm. The woman begins to bloom;
16 week- the date of the baby's movement helps to more accurately set the date of delivery, he actively moves every 10 minutes. He opens his eyes for the first time. Fetal movement may appear by the 20th week. Charging and the right menu improve the mother's condition;
17 week- the weight of the fetus exceeds 100 g, and the height reaches 12 cm. He and his mother need calcium, healthy food, since the body type is laid. A woman feels pressure in the stomach, liver. You have to eat many times a day in small portions so that the stomach has time to cope. Sometimes there are cramps in the legs due to a lack of B vitamins, magnesium, calcium;
18 week- the height of a small child is 13 cm, weight - 170 g, head diameter - almost 4 cm, fingers become proportional, foot length reaches 2.5 cm. Mothers rejoice, feeling his movements. At this time, there is a high probability of determining the sex of the baby on an ultrasound scan. The ideal weekly weight gain for a mom is 500 g. To reduce swelling, you need to consume less salt;
19 week- the child reacts to screams, the volume of the voice, turns the head to the sound. Listen to pleasant music, do not quarrel with your family. A pattern is formed on children's palms. Shocks in the tummy become more distinct. Women do not always distinguish the movement of the fetus from the processes that occur in the intestines;
20 week- the endocrine system is formed, the parts of the brain are improving, the baby can swallow, has good hearing, its weight is about 290 g, its height is about 24 cm. Mom's waist disappears from the rounding of the tummy, the first stretch marks appear, a comfortable bra is required;
21 weeks- if a baby is suddenly born after this period, its ability to survive increases significantly. Systems and organs are formed, the stomach and chest, head grow, subcutaneous fat is formed, receptors on the tongue distinguish taste, the first leukocytes appear in his body. Requires a lot of protein and 4 times more carbohydrates;
22 week- the brain weighs 100 g, the height of the fetus is 28 cm, the weight is about 430 g, the mass of the heart increases, the ligaments and vertebrae are clearly visible. It is necessary to consider the baby's movements, since swelling can compress the blood vessels that carry food to the placenta;
23 week- alveoli are formed, the respiratory system develops. Mom needs to drink plenty of water, because plasma is made up of it. On the head of the child, a fluff is noticeable during ultrasound examination, muscles, spine, bones, aorta are clearly visible;
24 week- Gradually, the skin of the baby is smoothed out, due to the appearance of subcutaneous fatty tissue. The baby feels the emotions of the mother. The doctor listens to how the heart beats, whether the breast, tummy has grown, what is the diameter of the head;
25 week- the weight of the child is 680 g, height - 34 cm. The bone marrow is connected to blood formation. In order for the alveoli to function, surfactant accumulates in the lungs. The bottom of the mother's uterus has risen to 25 cm, legs get tired more often, pain in the lower back appears;
26 week- the baby has grown to 35 cm, gained more than 770 g, smells, reacts faster to voices. The diameter of the head is now 65.1 mm, the abdomen is 67.4 mm, and the chest is 65.8 mm. By this time, the woman puts things off, spares herself more;
27 week- bookmark the speed of reactions, metabolic processes. Mom needs to gain strength for the upcoming third of gestation. The period is characterized by frequent shortness of breath due to a feeling of lack of air.

Third trimester: 28 weeks to delivery

The most difficult stage for a mother is from 7 months to childbirth. It is accompanied by the active growth of the baby, preparing the child for independent existence. Details:

28 week- the baby is exactly 7 months old, you can determine whether he will be right-handed or left-handed. To do this, the ultrasound shows which handle he often reaches for his mouth. There is already enough surfactant in the lungs so that the alveoli do not stick together during the first breath;
29 week- the growth of the baby has reached 38 cm, the weight is more than 1 kg. In the lubricant, he only has a tummy and folds. He becomes cramped inside his mother, and the blood fully protects him from infections, but venous and arterial blood is still mixed. The daily portion of urine excreted is 500 g. Mom is on maternity leave at this time;
30 week- the chest of the crumbs grew to 77.4 mm, and the tummy - to 79.3 mm. The cerebral cortex is formed, the child begins to remember some sounds, sensations. Mom will have to visit the gynecologist weekly. Due to the increased pressure on the vessels during sleep, the hands go numb, the legs cramp. The ligaments become elastic, you can do light stretching workouts in the pelvic area;
31 weeks- The child's weekly weight gain is about 200 g. The child needs subcutaneous fat to keep warm. The pigment accumulates in the hair and the iris of the eyes. Sometimes the uterus rehearses childbirth, one-time contractions appear;
32 week- the baby weighs 1700 g, the body length is over 40 cm. If the placenta "gets old", the nutrition will be disturbed, and deviations will appear in development. By this period, the first hair appears. The mother produces vasopressin and oxytocin;
33 week- the child has to take the fetal position, because there is not enough space. The body reached 43 cm, the head - 8.2 cm, the tummy - 87.4 mm, the breast - 85 mm. The placenta copes with the function of protecting the baby from harmful factors and nourishes it through the blood;
34 week- the baby weighs 2.1 kg. The placenta produces hormones that cause lactation. Its thickness is 3.39 cm. It is important not to overdo it with the use of calcium in order to exclude birth injuries. It is necessary to continue to count the movements of the fetus - 4-6 movements are considered the norm;
- childbirth is possible this week, but heredity determines a lot. The head is 1/4 of the body length, its diameter is 91 mm. Feet have been defined. The genitals and reflexes of the baby are developed. The placenta dries out, delivers nutrition worse. Mom is focused on the upcoming meeting with the baby;
39 week- the baby weighs 3.3 kg, height - 51.5 cm. Thanks to the fontanelles made of cartilage, the bones of the skull remain supple so that the child can pass through the birth canal. The baby will be able to distinguish objects at a distance of 30 cm from the eyes. The placenta ages and the fetus feels a lack of oxygen. Mom prepares things for the hospital and documents;
40 week- the child patiently waited for this hour, gained more than 3.5 kg, grew to 53 cm. The mother becomes anxious if childbirth does not occur. Before delivery, you often want to go to the toilet, the lower back aches, the cervix gradually opens, colostrum is released from the nipples.

If the birth did not occur at the 40th week, it does not matter. Resolution within 42 weeks is considered normal. It remains to trust nature. Only 10% of women in labor reach the 42nd week. Dopplerography and ultrasound are performed to assess the condition of the baby and mother. The main thing is to remain calm so as not to harm the health of mother and child.

"Cervix" in Latin means "cervix") or cervical canal. The cervix is 4 cm long and the width of the cervical canal is a maximum of 4 mm. The shape of the canal resembles a spindle, that is, its widest part is located in the center of the cervix, and the canal narrows up and down. This form ensures the preservation of the mucous plug, which is normally present in the cervical canal.

Description

This calculator will allow you to calculate what stage of pregnancy you are currently in, the date of future birth, the date of conception, and even the zodiac sign of the future baby and his zodiac animal according to the Eastern calendar. You can also determine the age of the fetus, its weight and height, and how much time is left before delivery. To do this, you need to enter the date of the first day of your last period and the length of your menstrual cycle. In addition, our calculator generates a very convenient and practical weekly pregnancy table. Using it, you can navigate which week of pregnancy you are currently in, as well as track the height and weight of your unborn child.

Many women, when they find out about their pregnancy, begin to experience a variety of feelings - some are overwhelmed with joy, others feel confusion. And, of course, every expectant mother has a lot of questions. They are especially interested in the day of the birth of their child.

Calculation By date of conception

It has been established that conception is possible only during ovulation, when a mature egg leaves the follicle to meet with the sperm. Ovulation usually occurs on the 14th day of the menstrual cycle (the period starting on the first day of the onset of menstruation and ending on the first day of the onset of the next). The duration of the menstrual cycle is different for every woman. It can be 28-35 days. On average, it lasts 28-29 days.

A woman planning a pregnancy or monitoring her cycle can accurately determine the day of ovulation. In addition, during this period, signs characteristic of it appear.

It is worth noting that the day of sexual intercourse may not coincide with the day of conception, since the viability of individual spermatozoa in a woman's body reaches up to 3 days.

So, knowing the day of ovulation, you can quite accurately calculate the date of birth. You just need to add 280 days to this day (the average duration of pregnancy). Please note that only a woman with a constant menstrual cycle can calculate the period of birth of a baby in this way.

We offer an online calculator that will help determine the period of birth of a child:

Calculate due date by month

Usually gynecologists use this method, it is called the obstetric period. When registering, the doctor will definitely ask the woman when she had her last menstruation. And, in order to calculate the day of birth, he will use the formula invented by the German obstetrician F.K. Negele: 3 calendar months are subtracted from the 1st day of the beginning of the last menstruation and 7 days are added. It is important to note that if the menstrual cycle is not 28 days, then this method of calculation is rather oriented.

Online calculator

(calculation will take a few seconds)

Date of birth by ultrasound

The most accurate way to determine the time of birth of a child is diagnostics by ultrasound (ultrasound), but it can only be used in the early stages of pregnancy (up to 12 weeks). Thanks to ultrasound, it is possible to determine the gestational age with high accuracy, and thereby calculate the date of birth. In the second trimester, the gestational age is determined according to the size of the head and limbs of the fetus, but since each child develops individually, the calculation error can be up to 7 days. In the third trimester, according to ultrasound, it is generally impossible to calculate the date of birth.

Date According to fetal movements

This method is not accurate. The error can be up to 2 weeks. But still, the expectant mother will have an idea when her child is approximately born. So, the first movement of the fetus during the first pregnancy, a woman can feel at 20 weeks, with the second at 18 weeks. It is known that it lasts 40 weeks. It turns out that in order to find out the approximate date of birth, you need to add 20 weeks or 22 weeks to the date of the first movement.

Unfortunately, it is impossible to calculate the birthday of a child using all these methods. Many factors can influence this. These include various diseases (polyhydramnios, diabetes mellitus, preeclampsia, multiple pregnancies, genetic characteristics, irregular menstruation, and others). According to statistics, only 10% of babies are born on the date set by the doctor when registering. Therefore, it is impossible to accurately calculate the date of birth, you can only approximately find out when the baby will be born.

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The pregnancy calculator allows you to calculate the exact due date and find out what week of pregnancy you are currently in, as well as the expected date of delivery. To calculate, select the date of the first day of your last period at the top of the calculator and click on the "Calculate" button. The calculator will then automatically display your current pregnancy week and expected due date.

For each week of pregnancy, two exact dates are displayed: the start day and the end day. The interval between them is exactly 7 days. You can scroll through the weeks of pregnancy using the arrows. The full list of weeks from 1st to 40th is at the very bottom of the calculator. By clicking on them, you can also scroll through the slider for the desired week. The trimester of pregnancy to which each week belongs is indicated by Roman numerals at the bottom (near the slider) and in the upper right corner of the cells (in the full list of weeks). Also, the trimesters are marked in pink, orange and blue, respectively. In general, the very concept of pregnancy trimesters is rather arbitrary and their boundaries are not clearly defined. We took as a basis the most common classification, in which the second trimester begins at the 14th week and ends at the 28th. Only your obstetrician-gynecologist can calculate trimesters more accurately after an ultrasound scan.

In the images you can see a rough illustration of the development of the baby inside the womb for each week. To the left of the images is a summary of the fetal growth for that week. For more complete and detailed information, you can find by clicking on the "More" link, which is located under each description.

Method for calculating the gestational age

The calculator calculates the so-called "obstetric" gestational age. It differs from the actual date by about two weeks. This calculation method is used in gynecology, because. it is very difficult to calculate the exact day of conception. Therefore, the calculation is based on the first day of the last menstruation, the date of which, as a rule, every woman remembers. 280 days or 40 weeks are added to this day. Thus, the first two weeks of the obstetric period you are not yet pregnant, because. ovulation has not yet occurred (based on an average menstrual cycle of 28 days). This method is not completely accurate because some women ovulate late or early. But, in general, for most expectant mothers, such a calculation turns out to be quite accurate.

In any case, we draw your attention to the fact that the pregnancy calculator allows you to calculate the term using the most general formula, which does not take into account the individual characteristics of your body. It cannot be used for self-diagnosis or any other medical purposes, since the results of its calculations are for informational purposes only. All precise calculations and any other manipulations should be done only by your attending physician.