The loose structure of the chorion is dangerous. What is a chorion? Symptoms and Diagnosis
During the obligatory ultrasound after 12 weeks, among other things, the location of the chorion is assessed. Sometimes an uzist will diagnose chorion previa. What does this mean and how dangerous is it?
What is chorion previa and why does it occur?
Until the placenta is formed, the embryo is surrounded by a villous membrane that grows into the uterine mucosa. Until the 16th week of gestation, this is the chorion (from the 17th week - the placenta), which performs the following main functions:
- Nutrition of the embryo;
- Respiration - delivery of oxygen and removal of carbon dioxide;
- Isolation of metabolic products;
- Embryo protection.
In the normal course of pregnancy, the chorion is attached to the bottom of the uterus, grows along the anterior, posterior and lateral walls, but this is not always the case.
Chorion presentation is its incorrect location, in which there is a complete or partial overlap of the internal pharynx of the cervical canal.
Why this condition occurs is not entirely clear. But a connection has been established with some factors:
- chronic inflammation of the uterus;
- transferred operations;
- nomal development of the uterus;
- a large number of pregnancies and childbirth;
- low implantation of the placenta in a previous pregnancy.
Types of location of the chorion
Based on the attachment of the chorion relative to the internal pharynx, presentation happens:
- Complete - a condition in which the chorion completely covers the internal pharynx. Subsequently, this will turn into placenta previa.
- Incomplete - characterized by overlapping of part of the uterine pharynx. If the villous membrane extends up to a third, then this 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.
Chorion previa at week 12 is not a final verdict. As the uterus and fetus grow, its migration may occur, and the condition will return to normal. A more favorable prognosis is noted for the posterior arrangement of the chorion and presentation along the anterior wall.
Complete overlap of the chorion of the uterine pharynx is a dangerous type of pathology that threatens with massive bleeding.
How is chorion previa manifested?
Most often, pathology is detected during ultrasound.
Bloody discharge can also be triggered by presentation, especially if a hot bath, sauna, sexual intercourse took place shortly before. In this case, you need to urgently consult a doctor.
Complications
Pathology is dangerous:
- premature miscarriage;
- uterine bleeding;
- intrauterine death of the child.
Chronic blood loss leads to the development of anemia and fetal hypoxia. While maintaining the complete overlap of the pharynx, childbirth in a natural way is impossible.
Treatment of chorion previa
Partial chorionic presentation without bleeding does not require hospitalization. The isolation of any amount of blood is an indication for treatment in the hospital.
It is impossible to artificially change the location of the villous membrane, so the main task facing doctors is to preserve pregnancy. In the hospital, a medical and protective regime is created:
- The woman is in a calm environment, observes bed rest;
- Physical activity is limited;
- A balanced diet is provided with the exclusion of foods that fix or relax the stool.
Medical treatment is as follows:
- Candles with Papaverine, Drotaverine tablets to relieve uterine tone;
- Iron preparations, for example, Totem, Maltofer - for the prevention or treatment of anemia.
In the presence of bleeding, the hemostatic drug Etamsylate sodium is additionally used. At the beginning of therapy, it is administered intravenously or intramuscularly. Then the transition to tablets is possible.
Massive bleeding that cannot be treated with conservative methods is an indication for termination of pregnancy.
After discharge from the hospital at home, it is necessary to 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?
Chorionic previa at 8-14 weeks can transform into a normal placenta or persist as a low placenta.
If the presentation did not disappear, but turned into anomalies in the location of the placenta, then by the time of delivery the child may be in the uterus transversely or with the buttocks to the bottom. In such cases, in order to reduce the risk, it is recommended to give birth through.
Prevention
Women should take care of their reproductive health as early as possible:
- Hypothermia should be avoided, inflammatory diseases of the genital area should be treated in a timely manner.
- Do not resort to abortion, this is not a method of family planning.
- It is important to eat properly and fully, to lead a measured lifestyle.
If you follow these simple rules, you will not have to get acquainted with pathologies from personal experience.
Yulia Shevchenko, obstetrician-gynecologist, specially for the site
Useful video
The health and life of the unborn baby depend on a huge number of factors.
Heredity plays a role, the behavior of the mother during pregnancy, her diet, daily routine, the presence of infectious diseases, congenital developmental abnormalities.
But not all pregnant women know that the success of bearing a child depends on the nature of the attachment of the fetus to the wall of the uterus.
Most often, expectant mothers who are faced with a diagnosis of chorion previa will learn about this.
What is chorion
Chorion is one of the fetal membranes that surrounds the baby in the uterus and provides a connection with the mother's body. This structure provides nutrition and respiration of the child, as well as the excretion of its metabolic products.
It is also a kind of barrier that protects a small organism from harmful influences.
The period of active functioning of the chorion is the first trimester, later it is replaced by the placenta, which will ensure the connection between mother and child until the moment of birth.
How is the chorion attached to the wall of the uterus
The chorion has many outgrowths-villi 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 the most favorable: when the uterus is stretched during the growth of the baby, neither the chorion in the first trimester, nor the placenta in the subsequent stages will be damaged or exfoliated, and the blood vessels will maintain integrity and ensure uninterrupted nutrition and breathing of the baby.
What is chorion previa
In some women, the chorion is attached to the lower part of the uterus. In this case, they talk about previa. According to the nature of its localization, there are:
1 low position- the chorion is attached to the lower segment of the uterus, but does not block the cervical canal (that is, does not block the path along which the child will move during childbirth).
In this case, severe bleeding may open, feeding and breathing of the fetus becomes impossible. Recommended.
3 Permanent violations of the connection between the placenta and the mother's body can cause fetal hypoxia (oxygen starvation), stunted growth and development, and in severe cases, death.
4 Although the low location of the placenta is considered the least dangerous for mother and child among all presentation options, it can cause complications in labor.
5 With complete placenta previa, natural childbirth provokes profuse bleeding, which can lead to the death of the mother and fetus.
Therefore, a caesarean section would be the only reasonable solution.
6 With full and partial presentation, a vaginal examination during a gynecological examination is not recommended, because it can cause bleeding.
Thus, placenta previa, especially complete, is a really dangerous phenomenon that causes a lot of difficulties.
But if this problem is detected on time, in the early stages of pregnancy, a woman has a high chance of having a healthy baby. However, control over the condition of the expectant mother and her child should be closer.
Interesting! Fourth month of pregnancy: development continues
Causes of chorion presentation
Perhaps the doctor will not be able to determine the factor that played a decisive role in the incorrect location of the placenta. The most common causes of previa are:
1
Congenital anomalies in the structure of the uterus, scars and defects in its wall, which occur due to previous surgical operations, caesarean section or frequent inflammatory processes.
2 Previa occurs more often in women who have a large number of children, or in those who have experienced this problem in a previous pregnancy.
3 A woman's age over 35 years is also a risk factor, the likelihood of placenta previa increases if a woman has bad habits (smoking is especially dangerous).
What awaits a pregnant woman if she is diagnosed with chorion previa
The expectant mother should be aware that in the case of placenta previa, she should be more careful and attentive. Most likely, you will have to spend some time in the hospital.
Some women with this diagnosis are forced to spend quite a long time in the hospital, 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 given to a woman during presentation are designed to eliminate complications (for example, to stop bleeding), or to maintain the condition of the mother and her child (multivitamins are often recommended, which can reduce the risk of a slowdown in development).
A woman throughout her pregnancy should observe a more gentle daily regimen, rest more, avoid physical and mental stress that can provoke bleeding. Sexual intercourse is often prohibited. If bleeding occurs, bed rest is recommended.
Content:
Normal maturity of the placenta at various weeks of pregnancy.
| Maturity | weeks of pregnancy |
| Zero (0) degree | 20-30 |
| First (1) degree | 30-34 |
| Second (2) degree | 34-37 |
| Third (3) degree | 37-39 |
Determining the degree of maturation of the placenta is necessary in order to understand whether the placenta is able to supply the developing child with sufficient nutrients.
How important is the thickness of the placenta?
As pregnancy progresses, the thickness of the placenta increases. This is a normal process. The thickness of the placenta is determined by ultrasound (see. ultrasound during pregnancy).
The normal thickness of the placenta at different stages of pregnancy is presented in the table below.
| Gestational age | Normal Thickness placenta in millimeters |
| 20 week | 16,7-28,6 |
| 21 weeks | 17,4-29,7 |
| 22 week | 18,1-30,7 |
| 23 week | 18,8-31,8 |
| 24 week | 19,6-32,9 |
| 25 week | 20,3-34,0 |
| 26 week | 21,0-35,1 |
| 27 week | 21,7-36,2 |
| 28 week | 22,4-37,3 |
| 29 week | 23,2-38,4 |
| 30 week | 23,9-39,5 |
| 31 weeks | 24,6-40,6 |
| 32 week | 25,3-41,6 |
| 33 week | 26,0-42,7 |
| 34 week | 26,8-43,8 |
| 35 week | 27,5-44,9 |
| 36 week | 28,2-46,0 |
| 37 week | 27,8-45,8 |
| 38 week | 27,5-45,5 |
| 39 week | 27,1-45,3 |
| 40 week | 26,7-45,0 |
As well as the degree of maturity, the thickness of the placenta is important in assessing how adequately the placenta provides for the development of the child.
What is premature aging of the placenta? How dangerous is it?
This paragraph was added after the question was received:
« … I am 36 weeks pregnant. At 33 weeks, they put 1-2 degrees of placental maturity, did cardiotocography (CTG), they said that the blood flow is normal, the child feels good. Recently I went for an ultrasound and they once again confirmed the premature aging of the placenta, the degree of maturity is 2-3, the thickness of the placenta is 32 mm, reduced.
Structural features of the placenta: lobulated with many calcifications. And so, basically, everything is fine with the baby, cephalic presentation, we weigh 2,300, it is fully developed, I haven’t done CT yet.
The date of birth is set approximately on March 17-18, but as in the maternity hospital at 33 weeks, and on ultrasound at 36 weeks, experts say that I can very possibly not deliver until the expected due date. I am very concerned
I was at the appointment with my doctor, she reacted absolutely calmly to this, as if everything was normal, somehow even strange, I thought she would tell me at least something, but she just keeps silent like a partisan, or maybe this silence from ignorance?!
Please help me resolve this issue!»
The aging of the placenta is spoken of in cases where calcifications appear in the tissues of the placenta (deposition of calcium salts in areas that have “already exhausted their resources” and do not function). Calcifications are clearly visible on ultrasound and it is this examination that is used primarily to determine the degree of maturity of the placenta.
To a certain extent, the gradual “shutdown” of placental tissues and the deposition of calcifications in them is a normal process (normal, physiological maturation of the placenta). It is believed that the placenta should reach the maximum degree of maturity (grade 3) for a period of 37-40 weeks.
Premature maturation (aging) of the placenta is said in cases where multiple calcifications (3rd degree of maturity) appear in the placenta in women who have not yet reached the age of 37 weeks. Usually, women learn about the premature maturation of the placenta after the next ultrasound, performed after the 30th week of pregnancy.
Quite often, the causes of premature aging of the placenta remain unknown. However, it is known that the development of this disorder can contribute arterial hypertension, gestational diabetes and smoking.
What complications can cause premature aging of the placenta? Does premature aging of the placenta always mean a threat to the development of pregnancy?
Despite the fact that signs of premature aging of the placenta are rarely found in women who have not yet reached 40 weeks of pregnancy, the detection of multiple calcifications in the placenta (grade 3 of maturity) does not always mean a threat to the development of pregnancy or the health of a pregnant woman. One 2011 study showed that the likelihood of developing complications largely depends on the gestational age at which premature aging of the placenta was detected.
As part of this study, the development of pregnancy was monitored in women from three groups:
- the first group included 63 women in whom premature aging of the placenta (3rd degree of maturity) was detected before 32 weeks of pregnancy;
- the second group included 192 women in whom premature aging of the placenta (3 degree of maturity) was detected in the period from 32 to 36 weeks of pregnancy;
- the third group included 521 women in whom no calcifications were detected in the placenta during the period from 28 to 36 weeks of pregnancy.
The results of the study showed that in women in group 1, complications such as premature birth, low birth weight, premature detachment of the placenta, bleeding after childbirth, stillbirth were observed much more often than in women from group 3. At the same time, among women from group 2, the risk of developing some problems during or after childbirth was the same as in group 3.
The results of this study suggest that the appearance of calcifications (stage 3 placenta) before 32 weeks of gestation does increase the risk of various complications, while the detection of signs of premature aging of the placenta after 32 weeks means that there are no serious grounds to expect any complications that may be related to this.
Currently, to assess the condition of the fetus in late pregnancy, doctors often prescribe a Doppler ultrasound with which the doctor can assess the condition of the vessels of the placenta and the rhythm of the fetal heart and, accordingly, the degree to which the fetus is provided with oxygen and nutrients.
In terms of assessing the ability of the placenta to support fetal development, Doppler ultrasound provides more information than conventional ultrasound, which can only assess the structure of the placenta. Many experts believe that with normal Doppler ultrasound, the presence of calcifications in the placenta should not cause concern.
What should I do if I have premature aging of the placenta?
As mentioned above, if signs of premature aging of the placenta appear before 32 weeks, fetal development may be impaired and the risk of other complications may increase. In this regard, if you have been found to have signs of premature aging of the placenta, the doctor may prescribe you a series of repeated ultrasounds, during which the rate of development of the fetus and its general condition will be checked. If doctors notice signs that the fetus is indeed receiving less oxygen or nutrients than it needs, they may recommend a caesarean section or induction of labor.
What happens to the placenta after childbirth?
Immediately after the birth of a child, the placenta (baby place) begins to quickly exfoliate from the uterine wall and, approximately 15-30 minutes after birth, is completely removed from the uterine cavity. This process is called the birth of the placenta. Due to the fact that the size of the placenta is much smaller than the size of a newborn baby, the birth of the placenta in most cases is easy and painless.
Immediately after the birth of the placenta, the gynecologist carefully examines it in order to determine whether a part of the placenta remains in the uterine cavity. Preservation of even small fragments of the placenta in the uterus can cause severe postpartum hemorrhage, and in the future may be the cause of infection and even a malignant tumor (see Chorionepithelioma).
What is the attachment of the placenta and chorion?
The development of pregnancy begins with the attachment of a fertilized egg to one of the walls of the uterus (see also how does conception occur?). As already mentioned at the beginning of the article, in the early stages of pregnancy, the fetus is attached to the wall of the uterus with the help of the chorion, at the end of the 1st trimester of pregnancy, the placenta forms in place of the chorion.
The uterine cavity can be schematically described as a cube. The developing embryo can attach to the upper, back, one of the side (right or left) or lower wall of the uterus.
Chorion refers to the so-called provisional or temporary organs, which are formed during the formation of the embryo of many animals, in particular, mammals, including humans. In this article, we will look at what a chorion is, what its functions are, and how the location of the chorion can be interpreted during an ultrasound scan.
Chorion: definition
Chorion, or as it is also called, serosa, is the outer shell of the embryo. This shell is adjacent to the maternal tissues. This shell serves for the exchange between the embryo and the environment of various substances, including nutrients. Also, the chorion has a filtering function, is able to synthesize some hormones. Its role for the fetus is really great, because in the future the chorion will become the placenta, through which the child will receive all the nutrients.
Chorion presentation
When scanning ultrasound, various defects of the chorion can be detected. Depending on this, the doctor can prescribe the appropriate types of treatment. Chorion previa is a special position of the membrane through which the child communicates with the environment of the mother. There are several types of presentation:
- Low presentation - characterized by the attachment of the fetal egg to the cervix. This is a fairly rare occurrence and occurs in only five percent of pregnant women. As the fetus grows, the chorion safely rises to the desired position.
- Presentation on the back or front wall of the uterus. These variants are the norm, and they are also characterized by the fact that the placenta can subsequently pass to the side walls.
- Regional or partial presentation can already be a threat. It is characterized by partial overlap of the cervix. With this type of presentation, the risk of miscarriage increases, but in this case, stationary rest is not required, usually everything is limited to the medical type of treatment.
- Central presentation is the most dangerous for mother and child. It is characterized by complete occlusion of the cervical canal. In such cases, hospitalization is recommended. The doctor must prescribe inpatient treatment and monitor the patient until recovery.
If you want to learn how to determine the sex of a child with the help of the chorion, then we recommend reading the article
In order to fully form intrauterine development, the fetus needs nutrition and oxygen. The chorion during pregnancy, and later the placenta, performs precisely this function, supplies all the necessary substances through the blood to the embryo.
What is chorion during pregnancy?
After fertilization and implantation of a fertilized egg, the fertilized egg needs nutrition and respiration. All the necessary substances come through the mother's blood at the beginning through the chorion, and later through the placental membrane.Thus, the chorion during pregnancy is, first of all, a temporary organ that guarantees the normal development of the embryo. The appearance of the chorion is a shell of the embryo with a large number of elongated villi that penetrate the wall of the uterus. Due to the growth of the fetus, the temporary organ also thickens, gradually transforming into the placenta, with the final changes occurring at 12-13 weeks.
In addition to the main function (nutrition and respiration), the chorion during pregnancy produces female hormones and protects the fetus. This means that the temporary body is designed to fully ensure the viability of the child.
Chorionic thickness by week of pregnancy: table
The first ultrasound examination is carried out for a period of approximately 12 weeks. During the examination, the attachment of the organ is assessed, which may differ and is not pathological. In this case, presentation is diagnosed along the posterior or anterior wall of the uterus, less often a low chorion is fixed, subsequently the organ often migrates to the side walls.Additionally, the chorion structure and thickness are assessed. Initially, the most thickened section of the chorion is subject to ultrasound measurement, which is approximately equal to the number of weeks of gestation in millimeters. The table shows the limits of the norms of the shell thickness in early pregnancy:
A significant thickening of the chorion is observed with diabetes mellitus or with the development of a hemolytic disease, while thinning indicates placental insufficiency and premature aging, which leads to spontaneous miscarriage.
Structural parameters of the chorion according to ultrasound
During the ultrasound examination, the doctor can record some parameters in the formation of the chorion, among which there are:- annular chorion up to 9 weeks indicates the normal development of a temporary organ, which subsequently transforms into a smoother and branched surface - the placenta;
- chorion cyst is the result of an inflammatory process, as a result of which there is no blood supply in one of the sections of the membrane. Such inflammation has little effect on the course of pregnancy;
- edema is diagnosed with an increased size of the shell, occurs due to the accumulation of fluid. It is not uncommon that this is considered a variant of the norm if there are no other pathological processes. In other cases, additional studies are prescribed to determine the causes of the edematous reaction.
- hypoplasia or loose heterogeneous chorion is associated with the fact that the villous structure of the organ breaks away from the walls of the uterine cavity, there is a risk of miscarriage.
Causes of chorion detachment in early pregnancy
During all 9 months of gestation, the chorion must be hermetically attached to the wall of the uterine cavity; in case of premature partial discharge, detachment of the chorion is diagnosed in early pregnancy. Complete detachment always leads to spontaneous abortion due to lack of nutrition to the fetus.The reasons for the discharge of the chorion are often associated with the older or younger age of the woman, with an asocial lifestyle (smoking, alcoholism), it is also observed with infectious lesions, during the development of more than one fetus in the womb, in the presence of abdominal injuries and blood clotting diseases.
Treatment of detachment of the chorion consists only in reducing the tone of the uterus due to special preparations and in complete rest for the woman. If placental abruption occurred in the later stages, when the child is able to live outside the mother's womb, then a decision is made to use delivery by caesarean section, otherwise the consequences threaten the life of both the mother and the child.
