Determination of gestational age

Determining the duration of pregnancy is the most urgent issue for a woman who recently learned about her interesting situation. Let's look at how to determine the duration of pregnancy, as well as the most accurate methods of determining the period.

Determination of the gestational age is a task not only for the pregnant woman, but also for the gynecologist. Since the correct time limit will allow you to monitor the course of pregnancy, prescribe the necessary tests and monitor the development of the baby. Knowledge of the term allows you to calculate the date of birth and the decree. A future mother's knowledge of the exact date of the appearance of the baby, helps to prepare mentally for the future motherhood and prepare everything necessary for the future child.

Gynecologists claim that knowing the exact period of pregnancy is one of the main aspects of monitoring and managing pregnancy. Methods for determining the duration of pregnancy and the accuracy of their results allow you to monitor the intrauterine development of the baby and prevent various pathologies. We offer you the most modern methods for determining the timing of pregnancy, as well as special calendar methods that will allow you to independently determine the duration of pregnancy.

[1], [2], [3], [4], [5], [6],

Early pregnancy detection

The definition of early pregnancy is important for a woman. So, almost 50% of embryos die in the first two to three weeks from the moment of conception. This is due to the fact that the fetus is helpless before the infection, which can be in the mother's body due to bad habits and other negative factors. Taking medication, smoking, prolonged exposure to the sun and drinking alcohol are the most common causes of embryo death in the first months of pregnancy. Many women may not know about their situation and continue to lead a fatal way for the development of the embryo lifestyle.

The definition of early pregnancy is also necessary for those women who plan to have an abortion. Because abortion in later terms can lead to infertility in the future, and serious complications. Medical abortions are performed during the first four to six weeks of pregnancy, and vacuum aspiration or mini-abortion within 20 days after the delay in menstruation and confirmation of pregnancy. Classical abortion (scraping) is done before the 12th week of pregnancy. But the optimal period for abortion and maintaining the health of a woman is a period of 6-8 weeks.

The onset of pregnancy is determined by various signs, both changes in appearance, and in the behavior of the pregnant woman. Frequent mood changes, vulnerability, changes in taste preferences, hypersensitivity, nausea (especially in the morning), puffiness of the limbs, delay in menstruation and swelling of the mammary glands may indicate early pregnancy.

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Methods for determining the duration of pregnancy

Methods for determining the length of pregnancy can determine how much time is left before delivery and how the future child develops. Let's look at the most popular methods for determining the duration of pregnancy.

• According to menstruation and the results of a survey of a gynecologist. In the early stages of pregnancy, the uterus increases to the size of a chicken egg.
• According to ultrasound - the accuracy of determining pregnancy using ultrasound is quite high in the first trimester.
• For ovulation - the gestation period can be determined by the date of the alleged conception, adding to it 14 days. This method determines the date of birth. For this, three months and seven days are counted from the date of ovulation.
• By bimanual examination - this method allows you to determine the duration of pregnancy by probing the position of the uterus. In the first trimester the uterus is in the pelvic area, and starting from the second trimester, it is probed above the bosom.

Pregnancy test

The test for determining the duration of pregnancy is a modern method to find out the time before going to the gynecologist. The most popular test among expectant mothers to determine the duration of pregnancy is Clearblue. The test is easy to use and gives the result with an accuracy of 99%.

The test for determining the term works on the same principle as a simple express test for determining pregnancy. To get the result, the test must be lowered into the urine tank or pissed on it. A couple of minutes on the electronic scoreboard will appear sand cups and the result is the gestation period. The only drawback of the test - the scoreboard with the result goes out after 24 hours. Therefore, if you want to share the result with relatives and relatives, you should hurry.

Clearblue with the definition of gestational age

Clearblue with the definition of pregnancy is a digital test that shows a double result on a special Smart Dual Sensor touchscreen. So, with the help of the test, you can not only confirm the pregnancy, but also learn its term. Let's look at the benefits of the Clearblue test.

• Now there is no need to examine the strips on the express test, since the digital display will show a reliable result, which will last for 24 hours.
• Clearblue is a one-of-a-kind test that provides information about the duration of pregnancy, that is, the amount of time elapsed since conception.
• The test gives a 99% accurate result from the first day of the delay.
• The test is very simple and easy to use.
• Clearblue has been approved by obstetricians and gynecologists around the world.

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Determining the period of pregnancy

The definition of the child's pregnancy is carried out in several ways. Some methods are based on the date of the last menstruation and the duration of the delay, the second on the signs of pregnancy that are manifested in a woman, and still others give an opportunity to learn the length of pregnancy with a digital test. Another way to determine the duration of a child's pregnancy is to undergo a gynecological examination or an ultrasound. Each woman decides independently which method to use. On average, after conception, it takes about seven days until the sperm fertilize the egg. That is why, many women are guided by the period of ovulation. Please note that it is recommended that you plan your pregnancy according to the timing of ovulation.

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Determination of the period of pregnancy by ultrasound

Definition of the term of pregnancy by ultrasound is one of the most reliable methods. The use of ultrasound in the first weeks of delaying menstruation allows you to accurately diagnose the timing of the pregnancy. Ultrasound is performed not only to determine the timing of pregnancy, but also to control the course of pregnancy and the development of the baby. Many gynecologists argue that the optimal period for reliable diagnosis of pregnancy is a period of up to 6 weeks. Diagnosis of pregnancy on ultrasound in a later period will be difficult.

The results of ultrasound in the first weeks after conception are based on the length of the embryo. The gynecologist measures the length of the fetus and compares the obtained data with tabulated values. This allows you to accurately determine the duration of pregnancy and monitor its course. During the entire pregnancy, a woman should make control ultrasound, so that the gynecologist can monitor the development of the child and, if necessary, prevent the development of pathologies.

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Determination of gestation by week

Determining the duration of pregnancy for weeks is the task of a gynecologist. Knowing the exact duration of pregnancy, which is calculated in weeks, the gynecologist controls the development of the child and the entire period of pregnancy. In addition, depending on the period, the doctor prescribes the delivery of certain analyzes and studies that will help prevent the development of pathologies and complications in the child.

Weeks of pregnancy are obstetric (for which we are observing) and embryonic. The obstetric period is 40 weeks, and the embryonic period is 38 weeks. To determine the exact time, the gynecologist observes the symptoms of pregnancy and the development of the embryo.

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Determination of the period of pregnancy for monthly

Determination of the period of pregnancy for monthly use is most often, since this method is fairly simple and effective. When examining a gynecologist and setting a gestation period, the doctor will know about the date of the last menstruation and the duration of the cycle. These data allow you to determine the duration of pregnancy on a monthly basis. Gynecologists use the method of counting the pregnancy from the first day of the last month. Since it is almost impossible to establish the exact date of conception, menstruation is the only landmark.

When establishing the gestation period, gynecologists use the calculation formula, where the menstrual cycle is taken as a basis in 28 days. This suggests that ovulation occurred on the 14th day after the onset of menstruation. But this formula is not always accurate, because not all women have a regular menstrual cycle. Therefore, the definition of the deadline has an error. Gynecologists distinguish two terms of pregnancy, the first - midwifery (from the first to the last day of menstruation), and the second embryonic (from the date of fertilization and ovulation).

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Table of the determination of gestational age

The table for determining the duration of pregnancy allows you to visually look at the expected date of delivery and the period of pregnancy. The table is based on the results of analyzes and gynecological examinations. There are several criteria that serve as a starting material in the table for determining pregnancy: the size of the fetus, the date of the last month and the results of the diagnosis.

We offer you a table for determining the duration of pregnancy based on the results of ultrasound, that is, the size and weight of the fetus. The size and weight of the embryo in the first trimester are not included in the table, because they are too small. Please note that the pregnancy determination chart uses obstetric pregnancy weeks.

A week	Height (cm)	Weight (gr)		A week	Height (cm)	Weight (gr)
Eleven	6-8	10-15		26th	33.5-35.5	850-1000
12	8-10	15-20		27th	35.5-37	1000-1200
13	10-12	20-30		28	37-38.5	1200-1350
14	12-14	30-50		29	38.5-40	1350-1500
15	14-16	50-75		Thirty	40-41	1500-1650
16	16-18	75-115		31	41-42.5	1650-1800
17th	18-20	115-160		32	42.5-43.5	1800-1950
18	20-22	160-215		33	43.5-44.5	1950-2100
19	22-24	215-250		34	44.5-45.5	2100-2250
20	24-26	270-350		35	45.5-46.5	2250-2500
21	26-27.5	350-410		36	46.5-48	2500-2600
22	27.5-29.5	410-500		37	48-49	2600-2800
23	29.5-31	500-600		38	49-50	2800-3000
24	31-32	600-750		39	50-51	3000-3200
25	32-33.5	750-850		40	51-54	3200-3500

Determination of the exact period of pregnancy

The exact period of pregnancy can be determined in several ways. Each of them has an error, let's consider the most popular ones.

• Symptomatic - the duration of pregnancy is determined by certain symptoms. So, breast augmentation, absence of menstruation and hypersensitivity testify to the early term of pregnancy. True, this method is very controversial, because in some cases, the above symptoms can talk about complications in the female body, and not about pregnancy. That is, the exact method is 50%.
• Ultrasound is a popular method for determining the duration of pregnancy. The accuracy of the results of ultrasound in determining the term is 100%.
• Digital tests are a modern method of determining the duration of pregnancy. The accuracy of the tests is 99%.
• Gynecological examination is the most accurate method of determining the period. With the help of the examination and the results of the tests, the gynecologist determines the gestational age. The accuracy of this method is 100%

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Pregnancy calendar

The calendar for determining the duration of pregnancy is based on the formula of Negele. Nine months and seven days of pregnancy are added to the date of the last menstruation (at the beginning) and take three months. To the received date it is necessary to add seven more days, the received result - the preliminary date of birth. According to this formula, there is a special calendar.

If you do not trust the calendar method, you can check its effectiveness. Calculate the date of birth according to the calendar and check it with the one that the gynecologist will tell after the examination. Pay attention that when determining the duration of pregnancy, the fetus stirs is of great importance. It is with the help of the date of the perturbation that the exact date of birth can be calculated. In this case, for women who give birth for the first time, by the date of the shift, 22 weeks are added, and those who have given birth again 20 weeks.

Determination of the gestation period for hCG

Determination of the gestation period for hCG is one of the most accurate methods. HCG or human chorionic gonadotropin is a hormone-protein that produces envelopes of the embryo throughout the pregnancy. It hCG blocks in the female body the processes responsible for the menstrual cycle, and increases the production of hormones that are responsible for maintaining the pregnancy. HCG increases during conception and acts as one of the reliable signs of pregnancy. The level of hCG rises from the first week of pregnancy, that is, within 14 days after conception. This indicator doubles every day, starting from 3 weeks of pregnancy and up to 12 weeks. From 12 to 22 week the level of the hormone does not increase, but from 22 weeks it starts to grow again.

The rate of increase in hCG in the blood makes it possible to determine the deviations in the development of pregnancy. So, with a frozen or ectopic pregnancy, hCG is below normal. A sharp increase in this indicator indicates a multiple pregnancy or a chromosomal disease. Therefore, a gynecologist, like the pregnant woman herself, should monitor the dynamics of hCG concentration in the blood during pregnancy. Let's consider the norms of the content of hCG and the influence of this hormone on the determination of the gestational age.

Days past the last menstruation	The hCG levels for this period of md / ml	Gestational age
26 days	0-50	12 days
27 days	25-100	13 days
28 days	50-100	2 weeks
29 days	100-200	15 days
30 days	200-400	16 days
Day 31	400-1000	17 days
32 days	1050-2800	18 days
33 days	1440-3760	19 days
34 days	1940-4980	20 days
35 days	2580-6530	3 weeks
36 days	3400-8450	22 days
37 days	4420-10810	23 days
38 days	5680-13660	24 days
39 days	7220-17050	25 days
40 days	9050-21040	26 days
41 days	10140-23340	27 days
42 days	11230-25640	4 weeks
43days	13750-30880	29 days
44 days	16650-36750	30 days
45 days	19910-43220	Day 31
46 days	25530-50210	32 days
47 days	27470-57640	33 days
48 days	31700-65380	34 days
49 days	36130-73280	5 weeks
50 days	40700-81150	36 days
51 days	45300-88790	37 days
52 days	49810-95990	38 days
53 days	54120-102540	39 days
54 days	58200-108230	40 days
55 days	61640-112870	41 days
56 days	64600-116310	6 weeks

Note that the values shown in the table are not a standard. Thus, depending on the characteristics of the woman's organism and the course of pregnancy, the rates of hCG in determining the duration of pregnancy also change.

Definition of gestation by conception

Determining the length of pregnancy by conception involves the calculation of the period by weeks. On average, the pregnancy lasts for 280 days or 40 weeks. The obstetricians determine the duration of pregnancy for menstruation and this is called obstetric pregnancy weeks. But the definition of the term of pregnancy for conception is called the embryonic period, and it is based on the period of ovulation. In every woman, conception occurs at different periods of ovulation, therefore, when determining the date of birth by conception, it is recommended to add 38 weeks to the date of the last menstruation.

But do not forget that midwives lead their pregnancy, which differs from embryonic (pregnancy by conception). And all the tests will have to pass, focusing on obstetric pregnancy.

Determination of the period of pregnancy for ovulation

The definition of the period of pregnancy for ovulation are simple and effective methods. Ovulation is the period of menstruation, in which pregnancy can occur, as a mature egg leaves the ovary and is ready for fertilization. On average, ovulation occurs on day 14 with a normal menstrual cycle at 28 days, and in women with a long cycle, ovulation occurs between 15 and 18 days. To accurately determine the period of ovulation, you can buy a special test or measure basal temperature. But some women can determine ovulation and for certain symptoms (pain in the lower abdomen, increased amount of vaginal discharge, increased sexual desire).

But the most accurate way to determine the duration of pregnancy for ovulation is ultrasound. Ultrasound can accurately determine ovulation. True, regular ultrasound is an expensive pleasure, therefore, other simpler methods are used to determine the timing of pregnancy.

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Determination of gestational age for KTP

Determination of the gestation period for CTE is possible only with the help of an ultrasound. At the beginning of pregnancy, a woman undergoes ultrasound, on which measurements of the fetal egg are made. KTP is the coccyx-parietal size of the embryo, which can be measured by visualization obtained by ultrasound. KTP is the maximum distance from the coccyx to the temechka. The KTR score is used to determine the exact duration of pregnancy during the first trimester. Let's look at these indicators:

KTP value, mm	Pregnancy, weeks
3	5
6th	6th
10	7th
16	8
23	9
31	10
41	Eleven
53	12
66	13

If the exact term of pregnancy is to be determined in the second or third trimester, then other indicators are used instead of KTP. Important is biparietal size or BPR, that is, the size between the temporal bones. Another indicator for determining the exact period of pregnancy is the abdominal circumference of the pregnant woman, the length of the thigh or femur. Let's look at the values of these indicators and the length of pregnancy. Fetometric parameters in the second and third trimesters of pregnancy:

Biparietal size, mm	Abdominal circumference, mm	Length of femur, mm	Pregnancy, weeks
24	61	12	14
28	72	16	15
32	78	20	16
36	96	24	17th
39	108	27th	18
43	120	Thirty	19
47	138	33	20
50	144	36	21
53	162	39	22
56	168	41	23
59	186	44	24
62	198	46	25
65	204	49	26th
68	216	51	27th
71	228	53	28
73	240	55	29
75	248	57	Thirty
78	259	59	31
80	270	61	32
82	278	63	33
84	288	65	34
86	290	67	35
88	300	69	36
89	306	71	37
91	310	73	38
93	324	74	39
94	325	76	40

All the above indicators use modern ultrasound devices when determining the duration of pregnancy. But, do not forget that the indicators may differ from the real ones. For example, when measuring CTE, the error may be in the week of pregnancy, and in the case of BPD, the error is up to 11 days.

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The formula for determining the period of pregnancy

The formula for determining the term of pregnancy is used by many women. Let's look at the most accurate and popular formulas.

• The formula of Negele for determining the date of labor for the last menstruation
• For calculation it is necessary to know the date of the last menstruation and deduct from it three months and seven days.
• Formula Jordania

The formula itself looks like: X = L + C, the value of X is the gestation period in weeks, L is the length of the embryo, and C is the head size measured by the tasometer. Let's look at this formula in practice. L - 18cm, C - 12 cm, that is, X = 18 + 12 = 30 weeks of pregnancy. But according to studies, in this formula there is an error of 2 weeks.

• The Skulsky formula

This formula allows you to accurately determine the duration of pregnancy in the last trimester. So, the formula: X = ((Lx2) -5) / 5, where X is the obstetric pregnancy, L is the length of the embryo, 2 is the coefficient that allows to determine the length of the fetus, 5 in the numerator is the coefficient of thickness of the uterine walls, in the denominator Is an exponent from the Haase formula.

• The Haas formula

A formula developed by an obstetrician-gynecologist to determine the fetal age of the embryo during the first 20 weeks of pregnancy. In the first 20 weeks, the length of the embryo in cm is equal to the square of the months of pregnancy, in the last 20 weeks - to the number of months of pregnancy multiplied by 5.

Accuracy of gestational age determination

The accuracy of determining the duration of pregnancy depends on the method used and the features of the course of pregnancy. To determine the exact date of the future mother will have to pass a lot of tests. The most accurate method is ultrasound, the use of digital tests and gynecological examination.

Determining the duration of pregnancy is important for every woman. Knowing the age of the embryo, the gynecologist can monitor its development, the course of pregnancy and prevent various pathologies and complications. In addition, the exact period of pregnancy allows you to determine the date of future births and prepare for a meeting with the baby.