Thickening of the placenta during pregnancy: causes. What degree of maturity and thickness should the placenta have? Does ultrasound determine pathologies such as placenta previa and abruption? What does the placenta look like on ultrasound?

The placenta or baby's place is an organ that appears at 12-14 weeks of pregnancy, the functions of which are the delivery of oxygen and nutrients to the unborn child, its protection from harmful factors and the synthesis of hormones. This structure is formed from the chorion - the primary fetal membrane. Normally, the placenta should be located in the upper part of the uterus - at its bottom, extending onto the front, back or side wall.

Low placentation during pregnancy- a pathology in which the organ does not reach the uterine os (the opening connecting the uterus and its cervix), but is located no further than 7 centimeters from it. Typically, this diagnosis is made at 20-22 weeks of gestation using ultrasound during the second screening. The low location of the child's seat is dangerous because various complications can arise against its background.

The mechanism of development of low placentation

7-8 days after conception, the fertilized egg enters the uterine cavity, where it attaches to one of its walls. Normally, embryo implantation should occur in the upper part of the organ. The physiological position of the fertilized egg is in the fundus of the uterus, but it can be located on the front, back, right or left side. If the embryo is fixed in the area of ​​the lower segment, obstetricians-gynecologists talk about.

By approximately the 14th week of gestation, the placenta is formed from the chorion, the place of attachment of which depends on the primary implantation of the fertilized egg. However, the uterus grows throughout the entire period of gestation, so sometimes the incorrect position of the membranes can become physiological by the middle or end of pregnancy.

Low placentation along the anterior wall is the most favorable variant of the pathology, since due to the abdominal muscles, the external uterine wall stretches well, and the baby's place moves along with it.

If the placenta is located on the back side of the organ, the chances of its normal position at the end of pregnancy are slightly lower. This is due to the fact that there is a spine behind the uterus, which prevents it from stretching too much.

The low location of the placenta should be distinguished from its presentation. The second diagnosis has the same etiology and development mechanism, but is a more severe variant of the first. Placenta previa is a pathology in which the baby's place extends onto the uterine os. Experts distinguish between complete and partial presentation.

With complete presentation, the placenta completely covers the uterine os. The pathology is accompanied by multiple and frequent complications; if it is detected, natural childbirth is impossible. With complete placenta previa, upward migration almost never occurs.

In partial presentation, the baby's place extends onto the uterine os, but does not completely cover it. This diagnosis has a more favorable outcome: upward migration of the baby’s place is possible, complications are less common, and in some situations, natural delivery is possible.

Causes of low placentation

Experts are not always able to determine the exact cause of incorrect implantation of the fertilized egg in a particular woman. Sometimes the development of low placentation occurs spontaneously without the presence of predisposing factors. However, doctors identify several reasons for improper embryo implantation. Most of them are associated with pathologies of the uterus, due to which the fertilized egg cannot settle in its proper place:

• congenital anomalies of organ development;
• chronic inflammatory process (endometritis, sexually transmitted infections, etc.);
• scar on the uterus as a result of surgical interventions;
• benign and malignant neoplasms;
• damage to the uterine wall after abortion or curettage.

Sometimes low placentation is associated with abnormalities of the embryo - its chromosomal mutations, as a result of which it cannot settle in a physiological place. Pathology also occurs against the background of severe extragenital diseases, especially with lesions of the circulatory and urinary systems. Low placentation can be observed when carrying twins, when the chorion of one of the embryos grows in the lower segment of the uterus due to lack of space.

The danger of low placentation

Low placentation itself does not affect the mother’s well-being; the danger of this pathology lies in possible complications. The most common consequence of an abnormal position of the baby's place is bleeding from the vagina. With low placentation, red discharge usually occurs after the 30th week of pregnancy, but sometimes it does not bother the woman at all. In more severe cases, uterine bleeding may appear at 23-24 weeks of gestation.

The reason for bleeding due to abnormal placentation is that the lower segment of the uterus is greatly stretched due to an increase in the weight of the fetus. The child's place does not have time to adapt to the stretching of the muscle wall, resulting in microdetachment. Its development is accompanied by exposure of the vessel, which leads to the release of blood from it.

Bleeding with low placentation has distinctive features. They almost always occur suddenly and are not accompanied by physical or emotional stress. Such bleeding is often observed at night. With low placentation, the discharge is scarlet in color and is not accompanied by pain. Bleeding tends to recur constantly.

Against the background of bleeding, accompanying complications sometimes occur - a drop in blood pressure and anemia. They impair the blood supply to the fetus, which can provoke hypoxia - oxygen starvation. Hypotension and anemia also worsen the well-being and performance of the expectant mother.

Attention! Low placentation may not manifest itself in any way in the first half of pregnancy, sometimes until the very end of the gestation period, so expectant mothers should not skip routine ultrasound examinations.

With chronic severe hypoxia, intrauterine growth retardation and development of the fetus develops. With this pathology, the unborn child lags behind its “peers” in weight and length by two or more weeks of gestational age. Intrauterine growth retardation and development of the fetus can provoke congenital pathologies of the nervous system and other organs, as well as death in the postpartum period.

Abnormal position of the placenta sometimes causes malposition- transverse (when the fetus is located transverse to the vertical axis of the uterus) and oblique (when the fetus is located at an acute angle to the vertical axis of the uterus). With these pathologies, it is impossible to give birth to a child without surgical intervention. Also, low placentation can provoke breech presentation - a position in which the fetus is born with the buttocks or legs, which complicates natural childbirth and often requires a cesarean section.

The most dangerous complication of low placentation is premature birth. They are observed as a result of detachment of a large area of ​​the child's place. The complication is accompanied by a shortening of the length of the cervix, opening of the internal and external pharynx and the onset of labor.

Marina Aist - low placentation and normal placental location:

Symptoms of low placentation

Quite often, low placentation does not manifest itself in any way for a long time. The main and only possible symptom of this pathology is bleeding, which has the following characteristics:

• scarlet color;
• not accompanied by pain;
• is not a consequence of physical activity;
• more often observed at night and at rest;
• tends to relapse.

If red uterine discharge is accompanied by cramping pain, it is a sign of premature termination of pregnancy. Indirect symptoms of low placentation that occur in response to repeated blood loss are constant weakness, decreased performance, “spots” before the eyes, and fatigue.

If any bleeding from the vagina occurs, a woman should consult a doctor immediately. The specialist conducts differential diagnostics, prescribes treatment, and performs emergency delivery according to indications.

Diagnostics

Currently diagnosis of “low placentation” is made using ultrasound examination when identifying the localization of the child's place near the uterine pharynx at a distance of 7 centimeters and below. Ultrasound at 19-21 weeks of pregnancy reveals this pathology in 2-3% of pregnant women. However, over time, the placenta can rise and take its normal position in the uterine cavity at the time of birth.

With an ultrasound examination, doctors can note indirect signs of low placentation. These include incorrect position of the fetus - oblique and transverse, as well as breech presentation. With a low position of the placenta, the unborn child in the last weeks of pregnancy cannot descend to the uterine os; it is higher than normal, as can be seen on ultrasound.

A woman with detected low placentation should visit a doctor at certain intervals to monitor the dynamics of the pathology. If there is a history of bleeding, the obstetrician-gynecologist should refer the expectant mother for a blood test for iron and coagulation parameters.

Treatment of low placentation

Once the diagnosis is established and there is no bleeding, the woman needs careful monitoring. If necessary, she is prescribed iron supplements to prevent the development of anemia. While at home, the expectant mother must follow a gentle regimen until the end of pregnancy.

With a low position of the placenta of the expectant mother Sexual activity is strictly prohibited. She should also eliminate physical and emotional stress and allocate enough time to sleep. A pregnant woman needs to eat properly and balancedly, including lean meat, fish, vegetables, herbs, fruits, cereals, black bread, and vegetable oil in her diet.

If bleeding occurs, the woman should immediately go to the hospital, where she will be given emergency treatment. The expectant mother is prescribed an oxygen mask and a dropper with a 0.9% sodium chloride solution. This therapy helps stop bleeding and replenish fluid loss from the bloodstream.

If these measures do not have the desired effect, doctors prescribe more serious drugs that stop blood loss. When this does not help stop the bleeding, the woman is indicated for emergency delivery by cesarean section.

Childbirth with low placentation is most often carried out naturally. During them, the woman should be under close medical supervision, since she may develop bleeding at any time. Often during the birth process, obstetricians-gynecologists resort to artificial opening of the amniotic sac. Indications for cesarean section are recurrent uterine bleeding of more than 200 ml, severe simultaneous blood loss and general contraindications to natural childbirth (improper position of the fetus, clinically narrow pelvis, etc.).

Prevention

Incorrect attachment of the placenta quite often occurs due to a disruption of the normal structure of the uterine mucosa. Therefore, to prevent this pathology, expectant mothers are advised to plan their pregnancy and avoid abortion. Women should also promptly treat infectious and inflammatory diseases of the pelvic organs.

When performing a cesarean section, preference should be given to incisions in the lower uterine segment and, if possible, avoid corporal surgery (when the incision is made along the midline of the abdomen).

Since low placentation may be caused by abnormalities of the ovum, the expectant mother should plan for conception. Before pregnancy, a woman is recommended to lead a healthy lifestyle - exercise, not have bad habits, and eat a healthy and balanced diet.

The placenta is a temporary organ that develops in a woman’s body during pregnancy. The baby's place has a complex structure; it connects mother and child without mixing their circulatory systems. The placenta is formed from chorionic villi from the moment the fertilized egg attaches to the wall of the uterus, provides the fetus with nutrients, supplies oxygen, removes metabolic products, and protects against infections. One of the key functions is the creation of a fetoplacental barrier.

This kind of filter protects the unborn child from everything bad. Beginning to fully function by 12 weeks, it allows some substances to pass through and delays the transport of others that are dangerous to the embryo and fetus. The baby's place produces hormones necessary during pregnancy and provides immunological protection for the fetus.

Development and maturation

These parameters can be determined by ultrasound. Three dimensions are measured: longitudinal and transverse, forming two perpendicular segments drawn through the points of the edges that are most distant from each other, and thickness (depth).

Typically, the placenta completes its formation by the 16th week of pregnancy, with a normal course without pathologies, and grows until the 37th week, reaching its maximum size by this time.

The first measurement of the child's seat parameters is carried out at 20 weeks. Further - according to indications. By the end of the gestation period, the thickness of the baby's place decreases. This size also has its indicators within the normal range, in accordance with the stage of pregnancy. It can vary within certain limits as long as there is no danger of disruption of basic functions.

In addition to the physiological thickness of the placenta, the degree of maturity of the baby's place is considered an important sign of the normal course of pregnancy. Thickening in combination with premature aging (involution) usually indicates pathology during pregnancy. A decrease in the functional capacity of this organ, which is important for the full intrauterine period of a child’s life, is called fetoplacental insufficiency.

Periods of development

As the child matures, it goes through a number of stages. They are tied to the time of pregnancy and at a certain period must meet certain parameters. There are 4 degrees of maturity:

• Zero degree – an organ of a homogeneous structure is formed, with a normal course of up to 30 weeks.
• The first is the growth and development of the organ, with the appearance of echogenic inclusions from 27 to 34 weeks.
• The second is a mature placenta, changing structure, multiple inclusions, period from 34 to 39 weeks.
• The third is the time of aging of the placenta, which occurs after the 37th week, the structure becomes lobed, and calcifications appear.

The normal thickness on average in millimeters is close in value to the gestational age by week; at 20 weeks the average thickening is 20 mm. Normally, on an ultrasound examination at 20 weeks, placental thickening ranges from 16.7 to 28.6 mm.

If the thickening has large parameters, we can talk about pathology. A thick placenta does not cope with its tasks so well and often leads to disruptions in life support and development of the fetus, and the hormonal levels of the pregnant woman.

Placental hyperplasia

The diagnosis of placental hyperplasia will alarm a woman both at 20 weeks during the first measurement of parameters on an ultrasound, and at any other time.

Hyperplasia or thickening of the placenta is a serious pathology during pregnancy, it can lead to chronic placental insufficiency.

Excessive growth of tissues, and not necessarily functional ones, disrupts the supply of oxygen and nutrition to the child. The excretory function also suffers. This can lead to slower fetal development, oxygen starvation, weight loss and complications of childbirth.

What is the threat of pathology?

Excessive hyperplasia of the placenta indicates rapid growth and premature aging of the organ with loss of its basic functions. The placenta changes its structure to lobulated, calcifications appear, which disrupts the normal supply of oxygen and essential nutrients from mother to fetus.

The child begins to suffer from oxygen starvation and malnutrition, and lags behind in development. In severe pathologies, there may be intrauterine fetal death and premature placental abruption.

The endocrine function of the organ is disrupted, which can cause pregnancy failure or premature birth.

Reasons for appearance

Any deviations from the norm in the body of a pregnant woman do not occur without a good reason and require study. This thesis also applies to placental hyperplasia. Most often, this condition is provoked by the following factors:

• Anemia during pregnancy, especially severe forms. Here we are talking about a compensatory mechanism.
• ARVI diseases. Viruses easily enter the placenta, destroy cells and disrupt their function.
• Diabetes. Glycosylated hemoglobin and other proteins are not able to adequately perform the tasks assigned to them, and the metabolism changes greatly.


• Chronic venereal and TORCH infections.
• Gestosis in late stages. Exposure to toxins often leads to damage to areas of the placenta and replacement of normal tissue with scar tissue.
• Multiple pregnancy. This is more or less a variant of the norm: in order to provide several children with everything they need, they have to increase in size.
• Low or overweight mother.
• Rh conflict between the blood of the mother and the fetus. A very serious reason. Indirectly indicates that the fetoplacental barrier is damaged, there is contact between the mother’s blood and the embryonic blood and there is a risk of fetal death.

If the mother has diabetes mellitus, there is another factor in the thickening of the placenta: pregnant women with this pathology are characterized by the development of a large fetus. To provide him with everything he needs, the child’s place is also forced to increase.

Gestational trophoblastic disease

One of the variants of the course is sometimes called incomplete hydatidiform mole. Occurs when one egg is fertilized simultaneously by two sperm, which leads to a genetic abnormality of the embryo. It occurs infrequently, but requires special attention, as it can cause oncological pathology.

Chromosomal abnormalities in 90% of cases lead to early termination of pregnancy, but in 10% the pregnancy does not stop. The placenta thickens in places, the size of the uterus corresponds to the duration of pregnancy. The fetal heartbeat can even be heard.

The diagnosis is made only by ultrasound examination and the sooner the better. The only option for help is curettage.

Clinical manifestations and diagnosis

External symptoms of placental hyperplasia of any origin are usually absent. Symptoms do not appear in the early stages; the diagnosis is established at the next ultrasound examination, starting from the 20th week of pregnancy. The thickness of the placenta is measured at its widest points.

There are no symptomatic manifestations of abnormal thickening of the placenta in the early stages up to 20 weeks.

This organ does not have painful nerve endings, so you can independently suspect hyperplasia only by indirect signs:

1. At later stages, when movement is already heard, at 18–20 weeks, a change in fetal movements is noted from activation to deceleration.
2. The appearance or increase in the intensity of gestosis, especially in the early stages.
3. Almost always there is a disturbance in the heartbeat when listening to cardiotocography.

Based on survey results. the doctor finds out the reasons, prescribes further examination for the pregnant woman (if necessary) and carries out symptomatic treatment based on the reasons that caused the thickening.

Ultrasound diagnostics

To determine the thickness of the baby's place, ultrasound is performed starting from 18–20 weeks. There is no point in delaying this study, since placental abnormalities detected early are easier to compensate for. The most important indicators:

1. Correspondence of the degree of maturity of the placenta to the gestational age.
2. Uniformity of structure.
3. Physiological tissue density.
4. The presence or absence of additional segments.

If the structure is preserved and the placenta is slightly thickened, no measures are required; dynamic monitoring is carried out.

The most important indicator is the condition of the fetus and what effect thickening of the placenta has on its growth and development, and whether it affects the normal course of pregnancy.

There is no more informative method for identifying placental pathology than ultrasound. Therefore, the timing of research cannot be neglected.

Prevention of complications

If a thickening of the placenta is detected by ultrasound before 20 weeks, there is no need to panic: the doctor will find out the reasons and give recommendations for the prevention of fetoplacental insufficiency. If necessary, treatment will be provided.

The woman herself can contribute well to the prevention of complications:

• You need to be outside more often.
• To refuse from bad habits.
• Eat well and eat well.
• Avoid contact with viral infections.
• Treat chronic infections at the planning stage of pregnancy.
• Control your weight and vitamin intake.
• Prevent anemia by getting tested on time.
• Regularly attend an antenatal clinic for early identification of causes that can be eliminated.

If the placenta is too thick and the reasons are clarified, the specialist prescribes therapy in accordance with the period in order to improve metabolism and support the fetus in the current conditions. Timely measures taken significantly increase the chances of giving birth to a normal child, even with significant thickening of the placenta.

When performing an ultrasound of the placenta, its thickness, location and degree of maturity are determined. There are four stages of placental maturity depending on the state of the chorionic plate, parenchyma and basal layer.

• Stage 0. The placenta has a homogeneous structure and an even chorionic membrane. The basal plate is not identified. This state of the placenta is typical for the second trimester of a physiologically occurring pregnancy.
• Stage I occurs at approximately 26 weeks of pregnancy; Separate echogenic zones appear in the placental tissue, the chorionic plate becomes slightly wavy, and the basal layer is identified.
• Stage II. From 32 weeks of pregnancy, stage II of maturity is diagnosed: the waviness of the chorionic plate increases, but the depressions do not reach the basal layer; in the latter, multiple small echo-positive inclusions appear; Evenly distributed echogenic zones are detected in the parenchyma.
• Stage III is characteristic of full-term pregnancy; it is distinguished by pronounced tortuosity of the chorionic membrane, reaching the basal layer, as a result of which on the echogram the placenta acquires a lobular structure, and a non-echoic space is visualized in the center of each lobule; a clear ultrasound picture of the cotyledon is formed. The onset of stage III before 35-37 weeks of pregnancy is usually regarded as premature maturation of the placenta - one of the indicators of placental insufficiency, which requires constant careful monitoring of the condition of the fetus.

The location of the placenta can be normal and pathological, for example, low attachment or placenta previa. The location of the placenta is determined during each ultrasound, starting from 9 weeks of pregnancy. During the examination, three parts are distinguished.

1. Chorial plate
2. Basal plate
3. Parenchyma of the placenta

The thickness of the placenta increases linearly until 32 weeks of pregnancy, then it may decrease. Normally, the thickness of the placenta is 3.15 cm. If the thickness of the placenta exceeds 4 cm, it is necessary to exclude a number of diseases.

• Diabetes in a pregnant woman
• Syphilis
• Erythroblastosis fetalis
• Nonimmune hydrops fetalis
• Congenital anomalies

Placenta previa is easily determined using ultrasound. However, if the placenta is located on the posterior wall of the uterus, difficulties arise in making a diagnosis due to the significant absorption of ultrasound waves by the presenting fetal head. Normally, as the uterus enlarges, the placenta gradually moves toward the fundus of the uterus. Placenta previa is often diagnosed in the second trimester of pregnancy, and by the end of pregnancy, if abruption has not occurred, its location becomes normal, i.e. The placenta is located above the internal os of the uterus. Therefore, a conclusion about the level of location of the lower edge of the placenta should be made only at the end of pregnancy.

Placental abruption can also be diagnosed using ultrasound based on the following signs.

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Everyone has heard about the placenta at least once in their life. But not everyone understands what it is, where it comes from and what function it performs during pregnancy. Nevertheless, during the period of waiting for the baby, great attention is paid to this organ, it is examined in detail using special methods, and the outcome of the pregnancy largely depends on it.

Future mothers often hear various stories about the placenta from their “experienced” friends: “I had a presentation. I was afraid I wouldn’t give birth”, “And they diagnosed me with premature aging of the placenta”... Let’s find out what really lies behind all these terms and whether everything is really so scary.

1. What is the placenta?

The name of the organ comes from Lat. placenta – pie, flatbread, pancake. The placenta that forms during pregnancy consists of lobules, each of which contains many small vessels. In this organ, two circulatory systems converge - the mother’s and the fetus’s. Small vessels unite into larger ones and ultimately form the umbilical cord - a cord-like formation that connects the baby and the placenta.

2. What functions does the placenta perform during pregnancy?

The placenta is a unique and very important organ that is temporary, that is, it forms and functions only during pregnancy. It is the placenta that ensures the normal functioning of the fetus. This is the connection between mother and baby. Through it, nutrients are transferred to the baby. During pregnancy, the placenta transports oxygen to the baby and takes carbon dioxide from it. In addition, it produces some necessary hormones. The placenta also carries out an important protective function - it acts as a so-called placental barrier, which “selects” which substances can penetrate to the baby, and for which “entry is prohibited.”

3. How should the placenta be located during normal pregnancy?

Typically, during pregnancy, the placenta is located closer to the fundus of the uterus (the so-called upper convex part of the uterus) along one of its walls. However, for some expectant mothers in early pregnancy, the placenta forms closer to the lower part of the uterus during pregnancy. Then we are talking about its low location. But if the doctor informed you about such a not very correct position of the placenta, you should not be upset. After all, the situation may well change. The fact is that the placenta can move during pregnancy (as doctors say, “migrate”). Of course, she does not move in the literal sense of the word. It’s just that the tissues of the lower part of the uterus are pulled upward as the duration of pregnancy increases, as a result of which the placenta also shifts during pregnancy and takes the correct position.

4. What is placenta previa during pregnancy?

Placenta previa is a much more serious diagnosis than placenta previa. We are talking about a situation when the placenta during pregnancy completely or partially closes the exit from the uterus. Why is such an incorrect dislocation of this organ dangerous? The placenta tissue is not very elastic and does not have time to adapt to the rapidly stretching wall of the lower part of the uterus, as a result, at some point it detaches and bleeding begins. It is usually painless and begins suddenly against a background of complete well-being. Bleeding repeats as pregnancy progresses, and it is impossible to predict when it will happen and what the next one will be in strength and duration. This is life-threatening for both mother and child, and hospitalization is necessary.

Even if the bleeding has stopped, the pregnant woman remains in the hospital under medical supervision until delivery. Placenta previa is diagnosed during pregnancy using ultrasound, and the final diagnosis can be made only after 24 weeks - before this there is a chance that the placenta will independently change position and move higher.

The reasons for the occurrence of placenta previa during pregnancy can be changes in the uterine mucosa as a result of repeated abortions, inflammation or sexually transmitted infections, or previous complicated childbirth. In the case of complete placenta previa, childbirth must be carried out by cesarean section, since other methods of delivery are impossible.

5. What is fetoplacental insufficiency?

If during pregnancy the placenta does not fully perform its work, then fetoplacental insufficiency (FPI) develops - a circulatory disorder in the “mother-placenta-fetus” system. If these violations are minor, then they do not have a negative effect on the baby. But it can also happen that FPN causes fetal hypoxia (lack of oxygen), as a result of which the baby may lag behind in growth and development. By the time of birth, such babies are often very weak and may suffer during childbirth due to injury. And after birth, they are more susceptible to various diseases. It is almost impossible to determine FPN “by eye”. To diagnose this complication during pregnancy, three main methods are used - ultrasound, Doppler and cardiotocography (CTG). At any slightest suspicion of FPN, all these examinations are mandatory.

At present, unfortunately, it is not possible to completely cure placental insufficiency during pregnancy. But doctors try to support the functioning of the placenta and, if possible, prolong the pregnancy until the optimal date of delivery. If even with the treatment of this complication the baby’s condition worsens, then an emergency caesarean section is performed regardless of the stage of pregnancy.

6. What does premature aging of the placenta during pregnancy mean?

Another pathology of the placenta is its early maturation or, as this condition is more often called, premature aging of the placenta. The placenta goes through several stages of development: formation (grade 0: up to 30 weeks of pregnancy), growth (grade I: from 27 to 34 weeks), placental maturity (stage II: from 34 to 39 weeks) and from 39 onwards - III degree. Premature aging of the placenta is the appearance of changes in it that advance the pregnancy period. The cause most often is previous colds, smoking, toxicosis and the threat of miscarriage, diseases of the respiratory and cardiovascular systems of the expectant mother.

Signs of premature aging of the placenta during pregnancy are determined by ultrasound. There is no need to be afraid of this diagnosis, but it is necessary to undergo a thorough examination: Doppler testing, which will provide additional information about the state of the uteroplacental blood flow, CTG and tests for possible infections. After the examination, the doctor will prescribe the necessary treatment.

Typically, a woman is advised to rest, walk in the fresh air, take vitamins and medications to prevent placental insufficiency during pregnancy. If the latter cannot be avoided, then the issue of early delivery is decided.

7. How is the condition of the placenta determined during pregnancy?

During pregnancy, the condition of the placenta and its work are the subject of close monitoring by a doctor. The position, development and structural features of this organ can be assessed by ultrasound. At the same time, the location and thickness of the placenta, the correspondence of its degree of maturity to the gestational age, the volume of amniotic fluid, the structure of the umbilical cord, and possible pathological inclusions in the structure of the placenta are determined.

To diagnose placental function, in addition to ultrasound, the following are used:

• laboratory methods– they are based on determining the level of placental hormones (estriol, human chorionic gonadotropin, placental lactogen), as well as the activity of enzymes (oxytocinase and thermostable alkaline phosphatase) in the blood of pregnant women.
• assessment of fetal heart function. In addition to simple listening, cardiotocography (CTG) is performed with an obstetric stethoscope, which is based on recording changes in the fetal heart rate depending on uterine contractions, the action of external stimuli or the activity of the baby himself.
• dopplerometry- This is a variant of ultrasound examination, which determines the speed of blood flow in the vessels of the uterus, umbilical cord and fetus. n

Expert opinion

Tatiana Panova. Candidate of Medical Sciences, obstetrician-gynecologist of the highest category

The placenta during pregnancy is an amazingly complex system, a well-coordinated mechanism, a whole factory that performs many different functions. But, unfortunately, any system, even the most perfect one, sometimes fails. For a variety of reasons, at different stages of pregnancy, deviations in the development and functioning of the placenta occur. Therefore, in order to prevent violations of its functions, it is important to carry out timely treatment of chronic diseases and give up bad habits, which often provoke problems associated with this organ. It is also important to maintain the correct daily routine: proper rest for at least 8–10 hours a day (sleeping on the left side is preferable - in this position blood flow to the placenta improves), eliminating physical and emotional stress, daily walks in the fresh air, and a balanced diet. You need to try to protect yourself from possible infection with viral infections, and also take multivitamins for expectant mothers.

Ekaterina Podvigina

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The patient should have a full but not overdistended bladder so that the lower uterine segment and vagina are clearly visualized. Ask the patient to drink 3 or 4 glasses of water before the test.

To examine the placenta, it is necessary to make multiple longitudinal and transverse sections. Oblique cuts may also be necessary.

Normal placenta

At the 16th week of pregnancy, the placenta occupies half of the inner surface of the uterus. At 36-40 weeks, the placenta occupies from 1/4 to 1/3 of the area of ​​the inner surface of the uterus.

Uterine contractions may simulate placenta or a mass in the uterine wall. Repeat the test after 5 minutes, but keep in mind that the contraction may last longer. If in doubt, wait a little longer.

Accurate determination of the location of the placenta is very important for patients with vaginal bleeding or signs of fetal distress, especially in late pregnancy.

Overdistension of the bladder can sometimes create a false echographic picture of placenta previa. Ask the patient to partially empty the bladder and repeat the test.

Location of the placenta

The placenta is easily visualized from 14 weeks of pregnancy. To examine the placenta located along the posterior wall, it is necessary to make oblique sections.

The location of the placenta is assessed in relation to the uterine wall and the axis of the cervical canal. The position of the placenta can be as follows: in the midline, on the right side wall, on the left side wall. Also, the placenta can be located on the anterior wall, on the anterior wall with extension to the bottom. in the bottom area, on the back wall, on the back wall with a transition to the bottom.

Placenta previa

It is extremely important to visualize the cervical canal if placenta previa is suspected. The cervical canal is visualized as an echogenic line surrounded by two hypo- or anechoic rims, or it may be entirely hypoechoic. The cervix and lower uterine segment will be visualized differently depending on the degree of bladder filling. When the bladder is full, the cervix appears elongated; lateral shadows from the fetal head, bladder or pelvic bones may obscure some details. With less filling of the bladder, the neck changes its orientation to a more vertical one and becomes perpendicular to the scanning plane. The cervix is ​​more difficult to visualize when the bladder is empty, but under these conditions it is less displaced and the relationship between the placenta and the cervical canal is more clearly defined.

The diagnosis of placenta previa, established during the examination with a full bladder, should be confirmed during the examination after its partial emptying.

Location of the placenta

1. If the placenta completely covers the internal uterine os, then this is central placenta previa.
2. If the edge of the placenta overlaps the internal os, there is regional placenta previa (in this case, the internal uterine os is still completely blocked by placental tissue).
3. If the lower edge of the placenta is located close to the internal os, there is low attachment placenta. It is difficult to accurately establish such a diagnosis, since only part of the uterine os is covered by the placenta.

The location of the placenta may change during pregnancy. If the study is carried out with a full bladder, it is necessary to repeat the study with a partially emptied bladder.

Placenta previa may be detected in the early stages of pregnancy and not detected at the end. However, central placenta previa is diagnosed at any stage of pregnancy, marginal placenta previa is diagnosed after 30 weeks, and after that no significant changes are noted. If no bleeding is observed in the second trimester of pregnancy, a second standard ultrasound examination of the placenta can be delayed until 36 weeks of gestation to confirm the diagnosis of previa. If in doubt, the test should be repeated before 38 weeks of pregnancy or immediately before birth.

Normal echostructure of the placenta

The placenta may be homogeneous or have isoechoic or hyperechoic foci throughout the basal layer. In the last stages of pregnancy, echogenic septa can be detected throughout the thickness of the placenta.

Anechoic areas immediately below the chorionic plate or within the placenta are often found as a result of thrombosis and subsequent fibrin accumulation. If they are not extensive, they can be considered normal.

Intraplacental anechoic areas may be caused by blood flow visible in dilated veins. If they affect only a small part of the placenta, they have no clinical significance.

Beneath the basal layer of the placenta, retroplacental hypoechoic channels can be seen along the uterine wall as a result of venous drainage. They should not be confused with retroplacental hematoma.

Pathology of the placenta

Hydatidiform mole can be easily diagnosed by its inherent echographic sign of a “snow storm”. It should be noted that the fetus may still be alive if the process affects only part of the placenta.

Enlargement (thickening) of the placenta

Measurement of placental thickness is too imprecise to significantly influence the diagnosis process. Any assessment is quite subjective.

1. Thickening of the placenta occurs with Rhesus conflict or fetal hydrops.
2. Diffuse thickening of the placenta can be observed in mild forms of diabetes mellitus in the mother.
3. The placenta may thicken if the mother has an infectious disease during pregnancy.
4. The placenta may become thickened with placental abruption.

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The hematoma may appear hyperechoic and is sometimes comparable in echogenicity to normal placenta. In this case, the only sign of a hematoma may be local thickening of the placenta, but the placenta may appear completely unchanged.

Ultrasound is not a very accurate method for diagnosing placental abruption. Clinical research remains extremely important.