Chorion is


"Preposition of the chorion" - such a diagnosis can be found in the medical record of a pregnant woman quite often. In the first half of pregnancy, “embryo” and “chorion” are medical terms that personify the child and the placenta, respectively. The presentation of the chorion suggests the place of attachment of the future placenta to the wall of the uterus, which may suggest further development of the fetus in the uterus. To accurately address the issue, you should understand such medical terms in detail.

The internal position of the chorion

Chorion - the continuation of the umbilical vein of the embryo. It is attached to the wall of the uterus, with the result that the embryo, and later the child, will receive all the necessary and useful nutrients that directly affect the development of the fetus.
The attachment of the chorion is formed in three places:

  • to the bottom of the uterus,
  • to the side walls
  • in the area of ​​the cervix, where there is a central, marginal, and incomplete presentation of the chorion.

The normal attachment of the chorion is its attachment to the bottom or to the sides of the uterus. In 10-12% of cases, the chorion is attached to the cervix. This position is called previa. Depending on the place of attachment, there are also several varieties of the presented diagnosis.

Presentation of the chorion at week 12 or 13

It should be noted that the presentation of the chorion at week 12 does not mean its permanent location right up to the birth. Very often there is a kind of migration. Similar processes are carried out up to 20 weeks. Sometimes it is possible to observe migration at rather late periods - practically just before the birth itself.

The presentation of the chorion at week 13 indicates the place of attachment in the cervical cavity. Such features of the development of pregnancy have practically no effect on the development of the fetus, however, one should not deviate from the general rules of preserving pregnancy. Typically, the chorion's presentation at week 13 prohibits sexual intercourse to pregnant women, as well as any weight lifting. You should not expose yourself to stress and physical activity.

Otherwise, the woman faces profuse bleeding with detachment of placental tissue. Therefore, a woman should take care of herself and her child, because excessive bleeding can provoke hemorrhagic shock, from which the expectant mother may die. Even the slightest bleeding threatens the child with the loss of the required amount of oxygen and nutrients.

Regional presentation of the chorion at week 13

As already described above, the presentation of the chorion has several varieties. They in turn affect the further development of the fetus, as well as the result of the form of delivery - natural or cesarean section. The regional presentation of the chorion at week 12 is the most favorable outcome that can develop with the presented pathology. This type of pathology may “withdraw” as a result of migration within a few days or weeks.

Regional presentation of the chorion is characterized by a partial overlap of the cervix. The presented species is divided into two subspecies. Thus, marginal presentation of chorion at week 13, where the future placenta covers no more than 1/3 of the cervix, and incomplete attachment, which entails more dangers and difficulties, are distinguished, since this diagnosis is made in the case of overlapping 2/3 of the cervix. Both subspecies have the property of migration, so the expectant mother should not worry. Most women give birth on their own, even if they had once had a diagnosis of a chorion edge presentation at 12 or 13 weeks.

Other Chorion Breeches

Low prevalence of chorion is found in only 5% of cases. This pathology is explained by the attachment of the future placenta 2-3 cm below the cervix. These features are diagnosed in pregnant women in the first two trimesters, therefore, we should not speak about any surgical interventions, because the placenta takes its normal positions by birth through migration.

The central presentation of the chorion is the cause of most cesarean sections. Most often, a pregnant woman in this case is already hospitalized for 4 months with a full examination and appropriate observation, since a complete overlap of the cervical canal of the cervix may cause unexpected uterine bleeding.

It turns out that the diagnosis of “regional presentation of the chorion” should not entail serious problems and provoke a serious nervous condition of a pregnant woman. In the presence of notation and diagnostics that are not clear to you, you should check with your doctor what the term means.

Conception process

For a start it is worth saying a few words about fertilization. In a healthy woman, a follicle ruptures once a month. At this point, a female gamete comes out, ready for fertilization.

If sexual intercourse takes place at this moment, the male cells will be able to meet freely with the egg cell. When two gametes merge, continuous division and movement of cells begins. When the formation reaches the reproductive organ, the ovum is attached. It grows tightly into the inner lining of the uterus and remains there for a long time.

Chorion - what's this?

Chorion is the outer fetal membrane of the embryo. It should be noted that the fertilized egg consists of two important components: the amnion and the chorion.

The outer part (chorion) is the most important part. It is she who borders the inner lining of the uterus. Localization of the chorion can be different. You will learn more about the most popular ones.

Chorion is a component of normal pregnancy. Without it, the fetus will not be able to develop normally and just die. This membrane appears approximately one week after fertilization and remains until the formation of the placenta. Many doctors say that the chorion is a placenta. To some extent, this statement is true. It is at the junction of the upper shell of the fetus with the endometrium that the placenta forms.

Chorion diagnostics

This formation can not be determined by vaginal examination. Chorion is an education that can only be seen with ultrasound. Always in the protocol ultrasound specialist describes the state of the structure, its location and features.

Chorion types

Medicine knows several varieties of the upper shell of the ovum. It should be noted that all of them depend on the duration of pregnancy and can vary greatly over time. To determine the type of chorion is possible only with ultrasound.

Gestational age up to 6 weeks from the moment of conception

At this stage of development of the ovum, you can detect the chorion ring-shaped. What it is?

On examination with the help of an ultrasonic sensor, you can detect a fetal egg. It is worth noting that the embryo is not visible at this time. The upper shell of the ovum is attached to the endometrium throughout its area. In this case, it can be said that a ring-shaped chorion takes place.

Gestational age up to 8 weeks from the moment of conception

Often in the ultrasound protocol, women will find a record: “Circular chorion”. What does it mean?

A similar condition of the upper fetal membrane is characteristic of early pregnancy. This kind of education is transformed at about 8 weeks after fertilization.

This type of shell is absolutely normal. Many women ask a gynecologist: "The chorionic villous: what is it?"

The shell received its name due to the fact that it has the so-called villi. It is with their help that it is attached to the inner wall of the reproductive organ. Villous chorion is always described in the ultrasound protocol. Also noted is its location.

Chorion localization

There are several common options for attaching this structure. Doctors still do not know why the fertilized egg chooses one place or another. We will understand each of the possible options.

This condition is the most common. In most cases, in the first trimester of pregnancy, chorion is found on the back of the genital organ. It is necessary to take into account the structural features of this shell.

If your chorion on the back wall is not located, then it is attached to the front of the uterus. This condition is also the norm, but it is necessary to observe special precautions.

With anterior localization, there is a risk of detachment of the membranes of the fetus. If you follow all the instructions of the doctor, you will most likely be able to avoid such complications. Do not panic when receiving such information. Chorion is able to move and migrate.

Chorion during pregnancy may be on the side. This situation is always reduced to the front or rear. At the same time indicate that the chorion is located, for example, front and right.

Preposition of chorion

Many pregnant women have to face this diagnosis. To get started is to find out what it means "presentation."

If the gestational egg is attached low in the genital organ, the resulting chorion will block the cervical canal or simply be located very close to the exit from the uterus. This condition is a pathology, but treatment for it has not yet been invented.

Do not be upset about the location of the chorion. He can migrate. The placenta can also move up or sideways. Thus, placenta previa, which was detected during the second screening, often disappears with a third ultrasound probe.

What could threaten the presentation of the chorion?

In most cases, this condition resolves on its own. However, there is a category of women whose chorion and placenta remain in place and do not move anywhere. What is it fraught with?

With this outcome of events, doctors can choose a non-standard delivery. If the placenta completely blocks the entrance to the uterus, then a planned cesarean section is performed. In the case when the chorion (placenta) is low, the doctor takes into account the distance between the cervical canal and the edge of the sheath. If the gap between the cervix and the placenta is more than five centimeters, then the woman is allowed to give birth on her own. In other cases, conduct a planned additional ultrasound a few days before delivery and, if necessary, appoint a caesarean section.


While waiting for a baby, women undergo various studies. Including ultrasound. With such an examination, the doctor always examines the chorion and notes its localization. This takes into account the size of the shell, the presence of detachments and other problems.

When applying chorion always follow the advice of a doctor. Only in this case, the pregnancy will end in successful delivery.

What is the presentation of the chorion and why does it occur?

Until the formation of the placenta, the embryo is surrounded by a villous membrane, which grows into the mucous membrane of the uterus. Until the 16th week of gestation, it is the chorion (from 17th week - the placenta), which performs the following main functions:

  • Nutrition of the embryo
  • Breathing - oxygen delivery and carbon dioxide excretion,
  • Isolation of exchange products,
  • Embryo protection.

In the normal course of pregnancy, the chorion attaches to the bottom of the uterus, grows along the front, back and side walls, but this is not always the case.

The presentation of the chorion is its wrong location, in which there is a complete or partial overlapping of the internal os of the cervical canal.

Why this condition occurs is not completely understood. But there is a connection with some factors:

  • chronic inflammation of the uterus,
  • transferred operations
  • fibromyoma,
  • development of the uterus,
  • a large number of pregnancies and childbirth,
  • low attachment of the placenta in the last pregnancy.

Types of chorion location

Based on the attachment of the chorion relative to the internal pharynx previa is:

  • Full - a condition in which the chorion completely overlaps the inner throat. Subsequently, it will go to placenta previa.
  • Incomplete - characterized by overlapping part of the uterine throat. If the fleecy sheath goes to third, then it is called marginal presentation.
  • Low - the chorion is located at a distance of 3 cm or less from the pharynx, but does not overlap it.

Prevailing chorion at week 12 is not a final verdict. As the uterus and fetus grows, its migration may occur, and the condition will return to normal. A more favorable prognosis is noted for the posterior location of the chorion and previa on the front wall.

The complete overlap of the uterine pharynx by the chorion is a dangerous type of pathology that threatens with massive bleeding.

Chorion Breech Treatment

Partial presentation of the chorion without bleeding does not require hospitalization. The allocation of any amount of blood is an indication for treatment in a hospital.

It is impossible to artificially change the location of the villous membrane; therefore, the main task facing doctors is to preserve pregnancy. An in-patient treatment and protection regime is created:

  • The woman is in a relaxed atmosphere, complying with bed rest,
  • Limited physical activity
  • Balanced nutrition is provided with the exception of anchoring or relaxing stool products.

Drug treatment is as follows:

  • Candles with Papaverine, Drotaverine tablets to relieve uterine tone,
  • Vitamins,
  • Iron preparations, for example, Totem, Maltofer - for the prevention or treatment of anemia.

In the presence of bleeding additionally used hemostatic drug etamzilat sodium. At the beginning of therapy, it is administered intravenously or intramuscularly. Then you can go to the pills.

Massive bleeding that is not amenable to treatment with conservative methods is an indication for termination of pregnancy.

After discharge from the hospital at home, you must adhere to a measured lifestyle, eliminate stress and increased stress. It is forbidden to have sex, because this can cause new bleeding and miscarriage.

What is the prognosis for pathology?

The presentation of the chorion at 8-14 weeks can be transformed into the normal location of the placenta or persist in the form of a low placentation.

If the presentation has not disappeared, but has passed into anomalies of the location of the placenta, then at the time of birth the baby may be in the uterus transversely or buttocks to the bottom. In such cases, in order to reduce the risk, it is recommended to give birth through cesarean section.


Women should take care of their reproductive health as early as possible:

  • Hypothermia should be avoided, timely treatment of inflammatory diseases of the genital area.
  • Do not resort to abortion, it is not a family planning method.
  • It is important to eat correctly and fully, maintain a measured lifestyle.

If you follow these simple rules, you will not have to get acquainted with the pathologies on personal experience.

What it is?

Chorion - a temporary body that performs the functions of a pharmacist. It is formed from the moment of the implantation of the ovum from the fallopian tube, where the meeting of the egg and spermatozoon, into the uterine cavity took place. As soon as the blastocyst (the fertilized egg turns into it by the 8-9 day after ovulation) reaches the uterus, it tends to gain a foothold in it. It is this process that is called implantation.

At the site of attachment of the shell, the blastocysts secrete special enzymes that make the mucous membranes of the uterus more pliable and allow the ovum to "grow". Chorion forms at the site of attachment. It is necessary for the nutrition of the ovum with useful substances from the mother’s blood. In its place a placenta appears a little later. But up to 12-13 weeks we are talking about the chorion, since the placenta is still being formed and does not function.

If the implantation is successful, the ovum is fastened in the area of ​​the bottom of the uterus (this is its upper part). If for some pathological reasons it was not possible to implant in the upper or middle part of the uterus by the blastocyst, it may descend into the lower uterine segment. And then the chorion will be formed low.

Preposition of the chorion is its location relative to the cervical canal - a thin passage inside the cervix connecting the uterine cavity and the vagina. About the presentation of speech is not only if the chorion was formed in the area of ​​the uterus or in its middle part (in the body of the uterus).

If the chorion is low, there are several types of presentation.


Depending on the degree of overlap of the cervical canal, through which the fetus will later pass in labor distinguish and types of pathology.

  • Regional presentation of chorion - the chorion is located low, its edge slightly affects the region of the cervical canal with one edge. Such presentation is considered the most favorable, in terms of projections, for further pregnancy and childbirth.
  • Incomplete previa - The chorion is located low and covers about two thirds of the entrance to the cervical canal. The predictions are less optimistic, since this position of the chorion in the uterus increases the likelihood of miscarriage or bleeding due to chorionic detachment.
  • Full previa - the chorion is formed low and completely closes the entrance to the cervical canal. This is a rather dangerous pathology, the forecasts for which are very unfavorable.

Any presentation of the chorion, but especially complete and incomplete, pose a threat of miscarriage, chorion detachment. In its place, a placenta will form, a network of blood vessels will develop, and it is dangerous if the vessels grow into the lower part of the uterus, which, according to the laws of nature, should open up and release the baby out when the time of birth comes.

Often, the presentation of the chorion can turn into another pathological condition - placenta previa, and then independent labor naturally will most likely be contraindicated. A woman will undergo a caesarean section. It will also be difficult to bring the child to the due time, since the low-lying and adjacent to the exit of the uterus placenta will create the risk of spontaneous bleeding at any time.

A child with a breech will receive less oxygen and nutrients, and this is fraught with hypotrophy and hypoxia.

Causes and symptoms

The main reason for the regional presentation is the internal prerequisites that prevented the ovum from implanting normally and into a more suitable bottom of the uterus. These prerequisites include endometrial disorders of the uterus. It is usually observed in women who undergo several abortions or undergo diagnostic curettage.

Miscarriages, missed abortion in history and also increase the likelihood of improper location of the ovum. An obstacle to full implantation may be a scar or several scars on the uterus from previous operations or cesarean section.

Women who have given birth to many, can not boast of strong and elastic muscle tissues of the reproductive organ, they also increase the likelihood that subsequent pregnancy may occur against the background of low placentation.

The presence of fibroids, fibromas and other formations in the upper part of the uterus also creates obstacles for the attachment of the blastocyst, and it is forced to descend in search of a “shelter” in the lower uterine segment. The reason may be a congenital anomaly of the structure of the uterus - two-horned or saddle-shaped uterus. Some sequence of such pathologies has been noticed - if during a previous pregnancy the woman had low placentation, with a high degree of probability the attachment of the fetus and the development of the chorion during the subsequent pregnancy will also be low.

Symptoms of the edge presentation of the chorion in the early stages may not be, and may appear a small short spotting. Usually they are always evaluated by a woman correctly - as a threat to the preservation of the child.

If the chorion, and subsequently the placenta, do not migrate, such bleeding associated with rupture of small blood vessels due to stretching of the walls of the uterus, can often recur, in some - until the birth. Because of them, a woman begins to suffer from anemia, she is chronically short of iron, and there is a small amount of hemoglobin in her blood. Be that as it may, when a bloody discharge from the genital tract of a pregnant woman appears, you should immediately call an ambulance.

With timely hospitalization with the help of conservative treatment, up to 90% of all babies growing up in the womb against the background of the regional presentation of the chorion, the placenta and even the umbilical cord can be saved.

What to do?

As already mentioned, the regional presentation of the chorion is diagnosed in about 4-5 women in ten pregnant women up to 12 weeks. However, not all of them immediately fall into the risk group and patient lists for elective cesarean section. Projections are favorable, and in 90% of cases the chorion, and then the placenta, which forms in its place, migrates higher simultaneously with the growth of the uterus.

Baby in the womb is growing rapidly. To meet its needs for comfort, the uterus and ligaments are forced to stretch. Together with them, "crawl" up and the placenta, which at the beginning of the pregnancy was located in the regional presentation. On the front or back of the uterus will migrate the placenta - does not matter. It is important that in most cases it really rises, and all the threats and risks associated with low placentation remain in the past.

Influence the process of migration, accelerate it or stimulate medicine can not. A woman with a diagnosis of “regional presentation of the chorion” needs to follow all the recommendations of her doctor, to eliminate physical exertion, weight lifting, jumping, sudden movements, squats. She will often have to visit her doctor, do an ultrasound to monitor the migration process of the chorion (placenta). Sex in marginal presentation is prohibited, because the orgasm associated with the contraction of the uterus muscles may contribute to rapid traumatic chorion detachment and the occurrence of severe bleeding, in which the child may die in utero, and the woman may lose a lot of blood and die from it.

The process of migration of the placenta is usually completed by 18-20 weeks of pregnancy. By this date or a little later (by week 35-28), the true state of affairs becomes clear - if the placenta has risen, the restrictions will be lifted, if not - the pregnant woman will be classified as at risk for preterm birth and will continue with increased attention and trembling.

It is impossible to accelerate the migration, but most likely, a woman will be prescribed treatment for a woman with a marginal presentation of chorion. Only it will be directed not at the chorion itself, but at relaxing the muscles of the uterus in order to prevent its tone and not to provoke new detachment and bleeding. Depending on the degree of presentation, treatment may be carried out in the hospital, and may be allowed to take the necessary drugs at home. This question the doctor leaves at its discretion.

A woman is shown bed rest or semi-bed rest, complete sexual and psychological rest. The following medications are effective: “Papaverin” and “No-shpa” antispasmodics, hemostatics - “Ditsinon”, vitamins of group B, “Magne B 6”, vitamin E in large dosages.

What is chorion

Chorion is one of the fetal membranes that surrounds the baby in the uterus and provides communication with the maternal organism. This structure provides nutrition and respiration of the child, as well as the removal of its metabolic products.

It is also a kind of barrier that protects a small body from harmful effects.

The period of active functioning of the chorion is the first trimester of pregnancy, later it is replaced by the placenta, which will provide communication between the mother and the baby until the moment of birth.

How is the chorion attached to the wall of the uterus

The chorion has many villous processes that are embedded in the wall of the uterus. They are penetrated by a dense network of capillaries and come into contact with the mother’s blood vessels.

Normally, the chorion is attached to the bottom of the uterus or its walls in the upper part.

This arrangement is most favorable: when the uterus is stretched during the growth of the baby, neither the chorion in the first trimester, nor the placenta at subsequent stages will be damaged or exfoliated, and the blood vessels will maintain integrity and ensure uninterrupted nutrition and breathing of the baby.

Complications of pregnancy with chorionic presentation

In cases where migration does not occur, and the incorrect location of the placenta in the uterus remains for the entire period of pregnancy, the woman should be prepared for some difficulties in carrying the child:

1 As the baby grows and the walls of the uterus stretch, the connection with the placenta can be broken. In this case, the blood vessels are torn, and periodically bleeding of varying intensity occurs.

2This situation often provokes placental abruption.

In this case, severe bleeding may open, feeding and breathing of the fetus becomes impossible. Cesarean section is recommended.

3 Permanent disruption of the connection between the placenta and the maternal organism can cause fetal hypoxia (oxygen starvation), growth and development retardation, and in severe cases death.

4 Although the low location of the placenta is considered the least dangerous for the mother and baby among all the options for presentation, it can cause complications of labor.

5 With full placenta previa, vaginal induction causes heavy bleeding, which can lead to death of the mother and fetus.

Therefore, a cesarean section will be the only reasonable solution.

6 With full and partial presentation is not recommended vaginal examination during gynecological examination, because it can cause bleeding.

Thus, placenta previa, especially the full, is really a dangerous phenomenon, which causes a lot of difficulties.

But if this problem is detected on time, in the early stages of pregnancy, the woman has a high chance of having a healthy baby. However, control over the state of the future mother and her child should be more closely.

Causes of Chorion Breeches

Perhaps the doctor will not be able to determine the factor that played a crucial role in the wrong location of the placenta. The most common causes of presentation are:

1Congenital abnormalities of the structure of the uterus, scars and defects of its walls, which arise due to previous surgeries, cesarean section or frequent inflammatory processes.

2 More often there is a presentation at the women who have a large number of children, or at those who faced this problem at the previous pregnancy.

3 The age of a woman over 35 years old is also a risk factor, the probability of placenta previa increases if a woman has bad habits (smoking is especially dangerous).

What awaits a pregnant woman if she is diagnosed with chorionic presentation

The expectant mother should be aware that in the event of placenta previa she should be more careful and attentive. Most likely, some time will have to spend in the hospital.

The doctor will recommend to go to the hospital, if there are periodic bleeding, even minor. Also, hospitalization is needed in the later periods, closer to the time of delivery.

With such a diagnosis, some women are forced to spend in the hospital for quite a long time, but the health of the child is more important, so you have to be patient.

This diagnosis cannot be eliminated by treatment. If the placenta itself does not change its location during pregnancy, then no external factors can affect it.

All drugs that are prescribed to the woman during presentation, are designed to eliminate complications (for example, to stop the bleeding), or to maintain the condition of the mother and her child (often multivitamins are recommended, which can reduce the risk of reducing the rate of development).

A woman during the whole pregnancy should observe a more benign regimen of the day, rest more, avoid physical and mental stress, which can provoke bleeding. Often prohibited and sex. When bleeding occurs, bed rest is recommended.

If you follow the recommendations of the doctor, the risk of miscarriage, premature birth and child death is significantly reduced. Therefore, a pregnant woman should remember her responsibility and try to do everything so that the baby is born alive and healthy.