Pregnancy period by ultrasound data table. Norms of the results of ultrasound of a pregnant woman in the first trimester. Key points of the fetometric study

Fetometry of the fetus is a method for determining the size of the anatomical structures of the unborn baby using ultrasound. Diagnostic data is checked against normative indicators to find out whether the baby is developing correctly in the womb.

Routine ultrasound examinations are performed three times: at 12, 20, and 32 weeks. The normal course of pregnancy gives reason to carry out fetometric diagnostics in the same period.

The procedure is carried out in two ways:

transvaginally - a vaginal probe is inserted into the vagina.
transabdominally - the contents of the uterus are examined through the outer abdominal wall.

During the examination, the doctor takes measurements of the fetal organs on the monitor screen, then makes a diagnosis about the correct development and formation of individual organs.

Additionally, fetometric analysis is usually carried out in such cases:

the mother's condition causes concern to the gynecologist;
there is a suspicion of a violation of intrauterine development of the fetus.

Key points of the fetometric study

The key data of the fetometric study are the following indicators:

DB - thigh length;
BPR - biparietal size;
DP - shoulder length;
KTR - coccyx-parietal size;
DN - the length of the nasal bone;
LZR - fronto-occipital size;
OG - head circumference;
DG - leg length;
OC - abdominal circumference;
TVP - the thickness of the collar space.

The decoding of the designations of the studied parameters is provided, since the fetometric data are written in the table in Latin.

A video about the stages of ultrasound was presented by the 1st Medical Quarter of Crede Experto on Taganka.

Baby weight

The body weight of the child by the 12th week is normally only 19 g, by the middle of pregnancy the baby will weigh about 345 g, and by the 32nd week - almost 2 kg.

If timely attention is paid to the problem with the discrepancy between the body weight of the fetus to the standard, and preventive measures are taken, then it will be relatively easy to correct the situation. The rate of weight gain is greatly influenced by the genetic factor. The gynecologist makes sure that the dynamics are positive.

KTP (CRL, coccyx-parietal size)

KTP (the Latin analogue of CRL) means the coccygeal-parietal size, that is, the growth of the child. It is calculated from the crown of the head to the end of the coccyx.

If this indicator slightly differs from the norm, then the fetus is not in danger. An increase in CTE over several weeks by the same value indicates that the fetus is relatively large.

BDP (BPD, biparietal and fronto-occipital head sizes)

The letters BPD denote the width of the fetal head. This is the maximum distance between the parietal bones. Size can be determined by taking measurements along the smallest axis of the circle between the temples of the child. BDP allows you to set the exact gestational age.

The parameter of the biparietal size of the fetal head (BDP) helps to identify developmental abnormalities already during the first trimester. The data obtained characterize the state of the fetal nervous system.

LZR or fronto-occipital size is calculated between the most distant points of the forehead and the back of the head.

OG (chest circumference)

The volume of the child's chest is determined by calculating the diameter of its circumference. A size that does not correspond to the norm should not cause much concern; most likely, this is a genetic feature. Perhaps the baby will just be born large. It is necessary to take into account the physical data of the mother and father.

OC (abdominal circumference)

Abdominal circumference is measured at 20 and 32 weeks of pregnancy. The parameter is calculated along the lines of the liver, stomach and umbilical vein. When the difference in indicators exceeds the permissible norm, the doctor will diagnose intrauterine growth retardation. However, to confirm it, the size of the coolant is calculated in relation to other parameters - the size of the head, thigh, BDP. If most of the indicators are normal, then this indicates a delay in the development of an asymmetric form.

DB (thigh length)

If a discrepancy is found in the indicator of the length of the thigh, then this also does not indicate the presence of pathology. Much depends on individual characteristics. For example, when the duration of the thigh and tibia is greater than normal, it means that the parents of the unborn baby or other relatives have a long leg.

PMP (PVP)

PVP is the estimated body weight of the fetus. During an ultrasound examination, there is a possibility of an error in weight. To eliminate the error, this figure is calculated using various medical formulas.

Calculation methods:

Zhordania (Lebedeva) - PMP \u003d standing height of the fundus of the uterus × abdominal circumference.
Bublichenko - PMP \u003d 1/20 of the woman's weight.
Lankovitsa - PMP \u003d (height + weight of the mother + abdominal circumference + height of the fundus of the uterus) × 10.
Jones - PMP \u003d (height of the fundus of the uterus - 11) × 155. The value of 11 is a conditional coefficient for a pregnant woman weighing up to 90 kg.
Yakubova - PMP \u003d (abdominal circumference + uterus standing height) × 100/4.

Calculations are made after 38 weeks of pregnancy.

The Family TV channel presented a video about an ultrasound scan in the third trimester.

Norms of fetometry of the fetus by week

Table of approximate norms of fetal development by week.

Gestational age	Weight, g	CTE, cm	OG (GDK), mm	dB, mm	BPR, mm
11	11	6,8	20	7	18
12	19	8,2	24	9	21
13	31	10,0	24	12	24
14	52	12,3	26	16	28
15	77	14,2	28	19	32
16	118	16,4	34	22	35
17	160	18,0	38	24	39
18	217	20,3	41	28	42
19	270	22,1	44	31	44
20	345	24,1	48	34	47
21	416	25,9	50	37	50
22	506	27,8	53	40	53
23	607	29,7	56	43	56
24	733	31,2	59	46	60
25	844	32,4	62	48	63
26	969	33,9	64	51	66
27	1135	35,5	69	53	69
28	1319	37,2	73	55	73
29	1482	38,6	76	57	76
30	1636	39,9	79	59	78
31	1779	41,1	81	61	80
32	1930	42,3	83	63	82
33	2088	43,6	85	65	84
34	2248	44,5	88	66	86
35	2414	45,4	91	67	88
36	2612	46,6	94	69	89,5
37	2820	47,9	97	71	91
38	2992	49,0	99	73	92
39	3170	50,2	101	75	93
40	3373	51,3	103	77	94,5

Tables of norms were created on the basis of world average data on pregnancy and fetal development.

The role of fetometry in assessing fetal development

The parameters and dimensions of the fetus obtained during the fetometric analysis allow the doctor to more accurately determine:

child health (for example, intrauterine growth retardation);
mother's condition;
date and outcome of the upcoming birth.

By changing the size of individual organs, the development of syndromes can be detected:

Down;
Patau;
Edwards;
Smith-Lemli-Opitz;
Miller-Dikker;
Williams;
Angelman.

Is it possible to calculate the height and weight of the child according to the results of ultrasound?

The height and weight of the embryo is determined by first knowing the following indicators:

obstetric gestational age;
head size (BPR, LZR, OG);
the length of the femur;
the size of the circumference of the abdomen and chest.

Calculator for calculating the height and weight of a child

From the moment of registration, the health of the woman and the fetus is closely monitored by obstetrician-gynecologists. Throughout the entire gestation period, the pregnant woman undergoes routine examinations. Some of the problems found can be solved therapeutically or surgically, others require termination of the pregnancy. One of the mandatory diagnostic methods that allows you to find out the parameters of fetal development is fetometry. How is fetometry done and what indicators are considered the norm?

What is fetometry and what is its purpose?

To have an idea about the development of the child (normally it passes or there are deviations), doctors need to constantly monitor the performance of the fetus. One of the planned examinations, which is prescribed to all women, regardless of the individual characteristics of the course of gestation, is fetometry.

What does fetometry include? This is the definition of the size of the fetus - height and weight. In ultrasound diagnostics, the following indicators are considered key (their abbreviation in Russian and English and decoding):

MP, FW - mass;
KTP, CRL - coccyx-parietal size;
BDP, BPD – biparietal head size of the embryo;
DB, FL - size of the femur;
OC, AC - abdominal circumference;
OG, NS - head circumference;
LZR, OFD - fronto-occipital size.

Fetometry is performed using ultrasound. A pregnant woman undergoes sonography according to the plan in each trimester - at 11-14 (most often 12th) weeks, 18-21 weeks and at 32-33 weeks. As a rule, sonography is performed in the usual way through the abdominal cavity or transvaginally. Special preparation for the study is not required, only in the first trimester before a transabdominal examination, a woman needs to drink 1 liter of water 1 hour before visiting the office so that the bladder is full.

Only by fetometry it is impossible to draw conclusions about the correct development of the fetus. The parameters of the child will largely depend on his genetic and individual characteristics. If the mother and father are large, then the baby will be ahead of their peers in development. In case of growth retardation, a second ultrasound scan is prescribed after 2 weeks, often the baby manages to catch up by this time.

What is evaluated at the first ultrasound?

The first screening ultrasound is sent shortly after the woman is registered. The optimal date for ultrasound diagnostics is 11–12 weeks, but if a pregnant woman went to the antenatal clinic later, she can be sent for sonography right away. Why is the screening examination scheduled for these periods? One of the most significant indicators in the early stages of gestation is the thickness of the nuchal space of the embryo. Previously, this parameter is indistinguishable, and after the 14th week it is filled with lymph, which distorts the readings.

Normal performance

At the first ultrasound, the doctor measures the heart rate of the fetus, looks at the presence of vital organs. Also pay close attention to the following parameters:

TVP - the area between the soft tissues that cover the spine and the inner surface of the skin. Allows you to detect chromosomal abnormalities, such as Down syndrome.
KTP - coccygeal-parietal size. It calculates the size of the fetus and the gestational age.

The table contains the norms of the results of ultrasound in the 1st trimester:

What does an embryo look like compared to a fruit? Until the first month, it resembles a poppy seed in size. By the end of the second month, it corresponds to a large grape of 5 cm. During the first fetometric study, it is comparable to a ripe fig of 7 cm.

What is considered abnormal and why?

To determine the norm and deviations in medical practice, the concept of percentiles is used. Among a large sample, the average value is determined - it is called the 50th percentile. The norm of ultrasound is in the range of 5-95 percentiles, and everything that goes beyond these limits is regarded as a deviation.

Non-compliance with normal values indicates the possibility of intrauterine diseases and developmental anomalies:

Increased TVP often indicates the presence of genetic pathologies, which include Down's syndrome. Its probability is indicated by a high TPT rate, which stands for the thickness of the prenasal tissue. If a discrepancy is found, the woman is sent for additional examinations - analysis for alpha-fetoprotein, hCG, amniocentesis, placentocentesis, cordocentesis.
Irregular heart rhythm may be due to congenital heart disease or hypoxia. Tachycardia and bradycardia can indicate oxygen starvation.
A high KTR, which is 1–2 weeks ahead of the values, is considered the norm by doctors. Most often, this indicates that the child will be large. If the mother has diabetes mellitus or the likelihood of developing an Rhesus conflict is increased, then additional examinations are required.
If deviations in the fetal anatomy are detected (incorrect anatomy of the bones of the cranial vault, spine, stomach, heart, limbs, abdominal wall), the sonologist enters them in a special column. Together with an obstetrician-gynecologist and, if required, geneticists, a conclusion is made on the advisability of prolonging gestation.

What indicators are studied in the second trimester?

Previously, ultrasound diagnostics in the second trimester was performed at the 25th week of pregnancy, but now it is performed at the 4th month of gestation. This is due to the need to detect malformations at an earlier stage. In addition to the parameters of the fetus during this period, they study the children's place, its size and degree of maturity.

Standard sizes

In the second trimester of pregnancy, you can better consider the size of the baby and specific organs. During this period, more attention is paid to the following indicators of ultrasound:

baby weight;
height;
abdominal circumference;
fronto-occipital size;
biparietal head size;
leg size;
thigh length;
humerus size;
forearm bone length.

The table shows the results of fetometry in the 2nd trimester in accordance with the protocol:

Week of gestation	Weight, g	Length cm	coolant, mm	OG, mm	LZR, mm	BPR, mm	DG, mm	dB, mm	DP, mm	DKP, mm
16 week	100	11,6	88–116	112–136	41–49	31–37	15–21	17–23	15–21	12–18
17 week	140	13	93–131	121–149	46–54	34–45	17–25	20–28	17–25	15–21
18 week	190	14,2	104–144	131–161	49–59	37–47	20–28	23–31	20–28	17–23
19 week	240	15,3	114–154	142–174	53–63	41–49	23–31	26–34	23–31	20–26
20 week	300	16,4	124–164	154–186	56–68	43–43	26–34	29–37	26–34	22–29

On the second screening study, it is already possible to estimate the size of the placenta. At week 20, it fluctuates between 1.67–2.86 cm. Amniotic fluid index by week:

16 – 74–202;
17 – 78–212;
18 – 81–221;
19 – 84–226;
20 – 87–231.

What are deviations from the standard?

The advanced maturation of the placenta is most often observed in smoking mothers. In addition, this indicator is affected by the presence of diabetes mellitus, the development of preeclampsia, the appearance of intrauterine infections.

Polyhydramnios indicates malformations in the development of the child, Rhesus conflict. Oligohydramnios indicates severe abnormalities in intrauterine development, pathologies or the absence of kidneys in the fetus.

Visualization can be difficult due to the high content of subcutaneous fat. In this case, the doctor indicates in the protocol the cause of the difficulty - PZHK.

The second screening ultrasound allows you to detect pathologies of fetal development that were not visible at the first examination:

developmental delay, if the indicators are symmetrically below the specified norm;
asymmetric reduction of the femur, humerus, tibia and forearm indicate skeletal dysplasia;
an increase in the skull indicates hydrocephalus;
by measuring the face, one can judge the presence of such pathologies as cyclopia, anophthalmia, cleft lip and palate;
scanning the spine helps to detect its splitting;
the absence, underdevelopment or abnormal structure of the internal organs indicate intrauterine anomalies that are incompatible with life.

Fetometry parameters of the fetus in the third trimester

The third fetal ultrasound is prescribed for 32–33 weeks of gestation, although, according to individual indications, the period can be shifted by several weeks. During this period, the baby is already fully formed, and it becomes possible to assess malformations that were not visible before. Particular attention is paid to the placenta and amniotic fluid, as well as fetal presentation.

Table of sizes of the fetus, body parts and organs are normal

The final fetometry is important, because it is according to its results that doctors choose the method of conducting the birth process. In the final trimester, the average data on the size of the baby and its weight are also evaluated.

The table shows the average fetometry in the third trimester:

On ultrasound, the obstetrician-gynecologist looks at the presentation of the fetus, the tactics of delivery depends on this:

direct head presentation - natural delivery;
oblique, transverse or direct pelvic presentation - caesarean section (as a rule).

Possible deviations and their interpretation

Deviations from normal indicators allow predicting possible complications during the birth process and detecting congenital malformations. Interpretation of deviations:

Weight and height are more than normal. A large baby will complicate the delivery process. This may be an indication for surgical intervention, otherwise the woman in labor will rupture when the child passes through the birth canal.
Low location of the placenta. In such a situation, natural childbirth is acceptable, but the risk of bleeding is high.
In the third trimester, anomalies that did not appear before become visible. On the last examination, you can find a cleft lip, a cleft palate, an aneurysm of the vein of Galen.
Indicators below the norm allow diagnosing developmental delay syndrome. This diagnosis allows you to take timely measures to maintain the life of the baby.

Rules for decoding the result of an ultrasound specialist

The interpretation of ultrasound during pregnancy is performed only by a sonologist, and the diagnosis is made by an obstetrician-gynecologist, who is based on the indicators of ultrasound diagnostics and other methods. Calculation of indicators is based on obstetric weeks, which are counted from the date of the last menstruation. In fact, the fetus is 1.5–2 weeks younger, but in order to avoid errors in calculations, gynecologists use a reference system from the first day of menstruation.

One of the main rules that specialists follow when deciphering ultrasound is not to make a diagnosis based on the results of sonography alone. If an abnormal course of gestation is suspected, the pregnant woman is prescribed a second examination and sent for additional diagnostics.

Despite the fact that specific numbers are indicated in the ultrasound report - limb length, volume, height and weight, you should not try to interpret them yourself. The limits of the norm indicators are large, borderline data do not necessarily indicate deviations, and the expectant mother needs to protect herself from stress.

Each desired pregnancy is, of course, sincere joy and real happiness for a woman. It is so nice to feel when a new life is ripening inside: the tummy is gradually growing, feelings and habits are changing, more and more often the eye stops at a store with things for newborns, and at home - at the place where you plan to put a cradle ... Unfortunately, sometimes this idyll is destroyed in just a fraction of a second: the gynecologist diagnoses "pathology of intrauterine development", which means that the baby will be born defective.

What is fetometry?

Fetometry indicators are necessary in order to more accurately determine the duration of pregnancy, as well as to be able to diagnose visible developmental disorders in a child. Remember that sometimes the baby can be just small due to the fact that his parents are not tall. But, perhaps, the baby lacks nutrients and mommy needs to drink a course of vitamins - all this should be discussed with your gynecologist.

Fetometry includes:

Coccyx-parietal size or abbreviated - KTR, or growth rate;

Biparietal head size, abbreviated as BDP;

Measuring the length of the thigh, abbreviated - DB;

Chest diameter, abbreviated DHA.

To increase accuracy in fetal fetometry, several parameters must be investigated. Basically, before the 36th week of pregnancy, these are coolant, BDP and DB, but after that it is coolant, DB and DHA.

To more accurately understand the results obtained on ultrasound, you can study the table below.

Average values of fetometry of the fetus

pregnancy	Height, cm	Weight, gr	dB, mm	DGK, mm	BPR, mm
11	6,8	11	7	20	18
12	8,2	19	9	24	21
13	10,0	31	12	24	24
14	12,3	52	16	26	28
15	14,2	77	19	28	32
16	16,4	118	22	34	35
17	18,0	160	24	38	39
18	20,3	217	28	41	42
19	22,1	270	31	44	44
20	24,1	345	34	48	47
21	25,9	416	37	50	50
22	27,8	506	40	53	53
23	29,7	607	43	56	56
24	31,2	733	46	59	60
25	32,4	844	48	62	63
26	33,9	969	51	64	66
27	35,5	1135	53	69	69
28	37,2	1319	55	73	73
29	38,6	1482	57	76	76
30	39,9	1636	59	79	78
31	41,1	1779	61	81	80
32	42,3	1930	63	83	82
33	43,6	2088	65	85	84
34	44,5	2248	66	88	86
35	45,4	2414	67	91	88
36	46,6	2612	69	94	89,5
37	47,9	2820	71	97	91
38	49,0	2992	73	99	92
39	50,2	3170	75	101	93
40	51,3	3373	77	103	94,5

Remember that these are average values and the final diagnosis will be made by your gynecologist. No need to look for deviations in your baby, because each of them is an individual and may have its own characteristics.

The interpretation of ultrasound readings is carried out by two specialists - a doctor who conducts an ultrasound examination, and a leading gynecologist. The ultrasound doctor issues a conclusion with the established gestational age and information about the existing pathologies of fetal development or their absence. The gynecologist also assesses the degree of pathologies and decides what to do next for the pregnant woman.

Why do you need an ultrasound during pregnancy

Conducting an ultrasound analysis is caused by the need to examine the child in the womb for its pathologies or their absence.

Early ultrasound is carried out to determine the presence of pregnancy and its duration, the number of fetal eggs. This way of research is useful in that it can reveal an ectopic pregnancy - a dangerous condition that requires immediate medical intervention, up to surgical methods. If, with the help of ultrasound, this pathology is detected in the initial stages, the pregnant woman has the opportunity to avoid surgical intervention.

At the stage first screening (11-13 weeks) the walls of the uterus, the uterus itself and its appendages are studied, and the following indicators of the growth of the embryo are considered:

chorion - it contributes to the development of the placenta;
The yolk sac is an important component for the development of the embryo.

At the next ultrasound helps to identify existing pathologies, such as, the threat of miscarriage,. It is the timely diagnosis of deviations that helps to eliminate them and avoid subsequent complications.

At the second screening a number of indicators are examined, which then will need to be deciphered:

the uterus, fallopian tubes and the condition of the ovaries are examined;
fetometry is carried out, with the help of which the sizes of individual parts of the fetus are established and their compliance with the gestational age is assessed;
the state of the organs that connect the child with the mother (placenta, umbilical cord) is studied, the structure of the amniotic fluid is assessed;
the state of the internal organs of the child is analyzed.

On this ultrasound, some pathologies can be traced, such as oligohydramnios or too low attachment of the placenta. Thanks to ultrasound, it is possible to establish both curable and incurable fetal defects.

Third screening carried out for the following purposes:

identification of serious fetal malformations that cannot be detected in the early stages;
determination of fetal presentation (gluteal or head);
determination of the body weight of the child;
assessment of the risk of abnormal formation of the brain;
examination for a subject;
evaluation of the fetal heart rate - rapid or rare;
assessment of fetal growth;
assessment of the risk of developing heart defects in the fetus.

On ultrasound in the third trimester, you can already see the baby's lungs and their readiness to work in a normal environment in case of premature birth. In the last screening, great attention is paid to the skull, abnormalities such as cleft palate, cleft lip, etc. are monitored.

On the eve of the birth itself, ultrasound allows you to find out some of the nuances that may be important for the birth process itself. In particular, only thanks to ultrasound it is possible to see the entwined umbilical cord with 100% accuracy, and this is a very important aspect in the birth process, because it can become a threat both to the health of the baby and to his life.

Some pregnant women are prescribed Ultrasound more often than expected. These pregnant women include those who have: diabetes mellitus, blood and lymph diseases, negative Rh factor.

Deciphering fetal ultrasound

Already starting from the 11th week of pregnancy, the detection of fetal pathologies is allowed. In Russia, two main standard protocols are defined, according to which data is decrypted.

These studies are conducted at 11-13 weeks of pregnancy and at 19-22 weeks. In order to more accurately decipher the data, you need to know the norms of fetal development at different stages of gestation.

At this time, a detailed examination of the collar zone of the fetus is carried out - the area between the tissues and the skin in the neck area. The thickness of the collar zone is abbreviated as TVP. Normally, TVP should not exceed 2.7 mm.

The nasal ossicle is another parameter that is being investigated at this time. Normally, the bone should be visualized.

Another indicator that is measured at this stage is KTR (coccyx-parietal size of the fetus).

For a kid at 11 - At week 13, the KTR is considered to be within 45-80 mm.

In addition to KTR, the doctor evaluates the biparietal and fronto-occipital dimensions of the fetus. The first is the distance from one temple of the head to another and is normally up to 28 mm. The second - the distance from the frontal to the occipital bone - normally does not exceed 31 mm.

* Percentile is a descriptive statistics term. The average value is indicated in the "50th percentile" column, in the "5th percentile" and "95th percentile" columns - the minimum and maximum allowable values, respectively.

Separately, the doctor evaluates the diameter of the fetal egg ...

... and calculates the heart rate (HR).

If the indicators do not correspond to the norm, the pregnant woman is recommended to undergo a consultation with a geneticist and an additional examination.

Second fetal screening

The norms of fetal development in the second trimester are shown in the table:

If there are any changes in these indicators, deviations in the development of the child in the womb can be assumed. By the way, during the second screening, the fetus is seen much better than during the first one, so the doctor can judge not only genetic abnormalities, but also other defects (they are recorded separately in the examination protocol).

As part of the third screening, such baby parameters as height, weight, biparietal head size, hip and chest length are evaluated. The norms of the listed parameters are described in the table above. Below are the normal indicators of BDP and LZR.

During the 3rd screening, the doctor evaluates the condition of the placenta, its degree of maturity and thickness. The placenta is the link between a mother and her baby. It remains for the entire duration of pregnancy. It exists in order to nourish the child with the necessary nutrients.

IAI norms (amniotic fluid index)

Fetal size by week of pregnancy

Each trimester has its own research and measurements. The interpretation of ultrasound indicators helps to establish the size of the child at the time of its development.

Below is a table of the size and weight of the fetus by week. It is worth saying that the readings are average, may differ from reality. This is especially true in the last months of pregnancy.

A newborn can be born with a weight of 2300 grams, or it can be born with a weight of 4500 grams. And in fact, and in another case, he can be absolutely healthy.

Term in weeks	Height in cm	Weight in g
	6-9	11-16
	9-11	16-21
	10-12	20-30
	12-14	30-50
	14-16	50-75
	16-18	75-115
	18-20	115-160
	20-22	160-215
	22-24	215-270
	24-26	270-350
	26-28	350-410
	28-30	410-500
	30-32	500-600
	32-34	600-750
	34-36	750-850
	36-37,5	850-1000
	37-39,5	1000-1200
	38-40	1200-1350
	39-40	1350-1500
	40-41	1500-1650
	41-42,5	1650-1800
	43-44,5	1800-1950
	44,5-45	1950-2100
	44,5-46	2100-2250
	46-46,5	2250-2500
	46,5-48	2500-2600
	48-49	2600-2800
	49-50	2800-3000
	50-51	3000-3200
	51-54	3200-3500

Ultrasound examination of the placenta

Ultrasound of the placenta determines its size, echostructure, development.

When the placenta may be hyperthick:

at detachment;

with Rhesus conflict;

with dropsy of the embryo;

mild thickening may occur in women with diabetes mellitus;

if in the process of bearing a pregnant woman suffered an infectious disease.

The placenta has the same functions as the human body - it tends to be born, mature and fade. All these moments are absolutely natural. But if it happens, it is a pathology.

Exists 3 degrees of maturity of the placenta:

Idegree of maturity. Until the 30th week of pregnancy, the placenta is at the zero degree of maturity. At this time, it increases in size, nourishing the baby with all the useful elements. The structure is normally homogeneous, smooth. After 30 weeks, specks and waves may appear on the placenta, which indicate the beginning of the maturation of the placenta. If the appearance of these signs is detected earlier, then this process is called "premature aging of the placenta." In some cases, women are prescribed medication. The first degree should last up to 34 weeks.

IIdegree of maturity. This degree comes from 34 to 37 weeks. It already looks more prominent, wavy, the ultrasound shows an echostructure with speckles. If the second degree is indicated earlier than 34 weeks, then more detailed diagnostics and fetal CTG will need to be performed. All tests as a whole will show if there are any fetal pathologies. If the child suffers from hypoxia, outpatient treatment may be prescribed.

IIIdegree of maturity. This degree is established already at full-term pregnancy. The placenta is preparing for childbirth and its functions are reduced, its natural aging occurs. There are large waves and salt deposits all over the surface.

If the placenta does not correspond to its term, then there is a risk of premature birth.

Ultrasound of the umbilical cord of the fetus

An umbilical cord passes between the placenta and the fetus, which connects them together. Ultrasound examination determines the number of vessels in the umbilical cord, their condition, structure.

The umbilical cord has two arteries and one vein that feed the fetus. The vein saturates the fetus with oxygen, and the arteries serve as the output of processed products.

The length of the umbilical cord should normally be at least 40 cm.

Ultrasound allows you to see the entanglement of the umbilical cord, if any. Establishment of entanglement is not yet a reason for a caesarean section.

Ultrasound examination of amniotic fluid

In the process of ultrasound, the amniotic index is calculated, which indicates the amount of water. The index is measured according to a certain scheme:

the uterus is divided into two perpendicular strips, one goes along the navel line, the other longitudinally;

in each sector, measurements of the free distance between the fetus and the wall of the uterus are made;

indicators are summed up.

Normal values at week 28 will be AI readings of 12-20 cm. An increase in the value may indicate polyhydramnios, a decrease in indicators, respectively, of oligohydramnios.

* Percentile is a descriptive statistics term. The average value is indicated in the "50th percentile" column, in the remaining columns - the minimum and maximum allowable values, respectively.

In any case, this or that deviation indicates violations in the blood supply to the placenta.

Ultrasound of the uterus during pregnancy. The size of the uterus by week of pregnancy

When conducting an ultrasound of the uterus, its size is measured, its appearance is examined for the presence of myomatous nodes, muscle tone, and the thickness of the walls of the uterus is measured.

Before pregnancy, the thickness of the walls of the uterus is 4-5 cm, by the end of pregnancy, the uterus is stretched, its walls become thinner and are approximately 0.5-2 cm.

The normal length of the cervix is 3.5-4.5 cm.

Marianna Artemova, obstetrician-gynecologist, specially for website

Ultrasound during pregnancy has long become an understandable and familiar procedure, because it is the simplest, most reliable and informative method for monitoring the condition of the fetus. As a rule, a specialist diagnostician during the study determines the duration of pregnancy, and almost every patient takes this for granted, without thinking - how exactly does the doctor determine the timing? And how accurate? What parameters does it use for this?

The role of ultrasound

It is diagnostics using ultrasound that helps the child's doctors on the basis of indicators of a very different nature, but at the same time directly established for a more informative result.

Setting an exact date also helps to predict the date of birth, which is very important both from a medical point of view and simply to calm the expectant mother. It is also necessary to know the most accurate period in order to control the development of the fetus, its condition, the correlation of norms with reality.

How does the specialist determine the timing?

Some patients believe that it is enough for the doctor to look at the image on the monitor - and the "age" of the child immediately becomes visually clear, but this, of course, is not so. The specialist fixes the obtained data of the embryo and compares it with the variants of the norm. Usually, to help the doctor, there are fixed indicators, where all the relevant norms are written for weeks.

Quantitative indicators.

Table No. 1. Norms of indicators at 5-10 weeks of pregnancy.

	KTP (Coccygeal-parietal distance)	Diameter of the ovum (average value)	Yolk sac diameter (mean)
5	2	18
6	5	22	3
7	10	24	4
8	16	29	4,4
9	22	32	4,6
10	24-40	39	5

Table number 2.

Gestational age (in weeks)
11	17-21	10-16	52-73
12	22-24	17-21	58-83
13	25-27	23-28	73-95
14	28-30	27-31	84-110
15	31-33	32-39	110
16	34-37	41-49	111-135
17	38-41	45-54	122-149
18	42-47	48-59	131-160
19	48-49	52-63	142-174
20	50-53	56-67	154-186
21	54-56	61-72	167-200
22	57-60	65-76	178-211
23	61-64	68-80	190-223
24	65-67	71-85	201-236

Table number 3. Norms of indicators for the third trimester.

Gestational age (in weeks)	BDP (biparietal size) (in millimeters)	Fronto-occipital size (in millimeters)	Head circumference (in millimeters)
25	68-70	73-88	215-250
26	71-73	76-93	224-261
27	75-76	80-96	235-273
28	77-79	83-98	245-284
29	80-82	86-101	255-295
30	83-85	89-104	265-304
31	86-87	93-108	273-314
32	88-89	95-112	283-325
33	90-91	98-116	289-332
34	92-93	101-119	295-338
35	94-95	105-120	299-345
36	96-97	104-123	303-348
37	98-98	106-126	307-352
38	99-100	108-128	309-357
39	101-102	109-129	311-359
40	103	110-120	312-361

Table No. 4. Standards for the length of the fetus.

Gestational age (in weeks)	Embryo dimensions (in centimeters)
5	0,8
6	1,1
7	1,3
8	1,5
9	2,2
10	3,2
11	4,1
12	5,3
13	7,5
14	8,7
15	10
16	11,5
17	13,1
18	14,2
19	15,2
20	16,5
21	26,6
22	27,8
23	29,8
24	31
25	34,6
26	35,5
27	36,5
28	37,7
29	38,6
30	39,8
31	41,1
32	42,5
33	43,6
34	45
35	46,1
36	47,3
37	48,6
38	49,8
39	50,6
40	51,7
41	52
42	53

Table No. 5. Standards for the circumference of the abdomen of the embryo.

Gestational age (in weeks)	Abdominal circumference (in millimeters)
11	40-61
12	50-71
13	58-79
14	66-91
15	91
16	88-115
17	93-130
18	105-144
19	114-154
20	125-163
21	137-177
22	148-190
23	160-201
24	173-223
25	183-228
26	194-240
27	206-253
28	217-264
29	228-277
30	238-290
31	247-300
32	258-314
33	267-334
34	276-336
35	285-344
36	292-353
37	300-360
38	304-368
39	310-375
40	313-380

Table No. 6. Norms for the thickness of the placenta.

Gestational age (in weeks)	Optimal placental thickness (in millimeters)
20	22-23
21	22,8-23,5
22	23,6-24,4
23	24,5-26
24	25,3-25,8
25	26,2-26,7
26	27-27,5
27	27,9-28,3
28	28,7-29
29	29,6-30
30	30,4-30,7
31	31,3-31,8
32	32,1-32,5
33	33-33,4
34	33,9-34,3
35	34,7-35
36	35,6-36
37	34,3-34,7
38	34,1-34,5
39	33,8-34
40	33,5-33,7

What exactly is the specialist analyzing?

The analyzed indicators of the norm depend on the trimester and the specific period.

Particular attention is paid to the length of the fetus, since this is the only parameter that gives reliable information. During this period, there are no decisive differences in the development of embryos in different women, so ultrasound establishes the “age” of the child to the nearest day.

The second and , during which it is impossible to achieve absolute accuracy, because from this moment the embryos begin to develop individually. Doctors use average figures, but even in this case, the period is set as reliably as possible, and it is very possible to identify possible pathologies. At the same time, specialists analyze such indicators as the circumference of the child's head, the diameter of the chest, the coccygeal-parietal distance of the embryo.

Now it is necessary to analyze in more detail the meaning of the indicators presented in these tables, which may raise questions from patients.

distance, respectively, from the crown of the embryo to the coccyx. Thanks to this indicator, the most accurate determination of the term is possible, because these sizes are universal. Also, if there are factors preventing the setting of deadlines, KTR is the only reliable parameter in this case.

The diameter of the ovum is the directly fertilized egg from which the embryo will develop in the future. Its dimensions, of course, directly depend on the specific period and have long been studied - it is enough for the doctor to look at the corresponding table.

The diameter of the yolk sac is also an important indicator b, since the yolk sac plays a very important role throughout the development of the child (for example, in the first trimester it supplies the circulatory system of the embryo with nuclear erythrocytes). The dimensions are also always in the doctor's table.

Between the parietal bones of the embryo.

Fronto-occipital size- the distance between the frontal and occipital bones, respectively.

Embryo length- is calculated when the child is in the most "unbent" state.

Placenta thickness- a lot depends on the placenta: it protects the child, and supplies him with everything he needs, and produces many hormones. Therefore, it is very important to check for compliance with its thickness to the standards laid down by the deadline. If the mother's condition is stable, there are no deviations - it is enough to simply establish the "age" of the embryo by the thickness of the placenta.

Accuracy

Many women are interested in - how accurate is ultrasound of the fetus? Therefore, it is important to note that ultrasound diagnostics establishes obstetric dates, in other words, the “age” of the embryo is calculated from the first day of the last menstruation. Sometimes a situation arises when a patient, referring to tables on the Internet and ultrasound results, finds differences in terms, so you need to know exactly which system was used to calculate, and not “sin” for the imperfection of ultrasound diagnostics.

Pathologies

Ultrasound of the fetus is informative not only as an aid to determine the period, but also in the detection of pathologies of a different nature. Moreover, some of them can only be detected using ultrasound, it is also important to note that, since this is a fairly effective method of monitoring the condition of the fetus.

So, the main pathologies that can be determined are:

Developmental delay (detected by comparing normative parameters with reality, indicators below the threshold undoubtedly indicate the presence of an anomaly).
Various defects (also found when indicators do not match).
Low water.
Polyhydramnios.
Thickening of the placenta.
indicators below the standards (especially the coccyx-parietal size) in the first trimester).

When can I go to the diagnostic room?

Of course, modern ultrasound technologies make it possible to detect an embryo already, but most clinics still do not have such perfect equipment. It is also important to note that this will require transvaginal ultrasound, which is very dangerous for the unborn child and can cause spontaneous miscarriage. So early examination can be done only if there are special medical indications, in any other case, you can be patient with knowledge of the exact date.

It is advised to contact the diagnostician at the 5th week of pregnancy, when it will already be possible to examine the fetus in more detail using ultrasound, draw certain conclusions and set the period with maximum accuracy.

Is it dangerous?

Some patients refuse ultrasound diagnostics by both transvaginal and transabdominal methods, referring to the danger of ultrasound. Indeed, these fears are logical, because taking care of the health of the baby is characteristic of any mother. But for an embryo, even at a short time, there is no reason to believe that ultrasonic waves will harm the development of the child, cause pathologies or cause miscarriage.

Error Probability

Any woman can quite rightly consider that the size of the embryo is not the most reliable indicator for setting the term, because each child develops differently and it is difficult to determine its exact age. But in fact, over the years of medical practice, there can no longer be any doubt about the correctness of the period established on the ultrasound of the fetus.

If a woman still questions the results of an ultrasound scan, you can always carry out a number of additional diagnostic procedures, which in turn will allow you to determine the timing at the most accurate level.

Ultrasound of the fetus is not only a method for monitoring the condition of the fetus, controlling its development, but also quite reliable, accurate, informative, convenient and simple. » embryo, using special tables that a simple patient can rely on.