What is marginal presentation of the chorion and what does it affect?

Many terms and conditions during pregnancy can seem overwhelming, particularly if they have an impact on the health of your unborn child. The chorion’s marginal presentation is one of them. This term describes the early stages of pregnancy when the chorion attaches to the uterus and eventually forms part of the placenta.

It is referred to as marginal presentation when the chorion is situated close to the uterine border. Even though this sounds alarming, issues aren’t always guaranteed. Although the condition usually resolves on its own as the pregnancy goes on, it’s crucial to know what it means and what to look out for.

You and your healthcare provider can have more effective communication and stay informed about any necessary precautions or steps to ensure a healthy pregnancy if you are aware of the marginal presentation of the chorion. Let’s examine this condition’s symptoms and potential effects on your pregnancy.

What is it?

The chorion is a temporary organ that performs the functions of a pharmacist. It is formed from the moment of implantation of the fertilized egg from the fallopian tube, where the meeting of the egg and sperm took place, into the uterine cavity. As soon as the blastocyst (this is what the fertilized egg turns into by the 8-9th day after ovulation) reaches the uterine cavity, it seeks to gain a foothold in it. This process is called implantation. At the site of attachment of the membrane, the blastocyst secretes special enzymes that make the mucous membranes of the uterus more pliable and allow the fertilized egg to "grow". A chorion is formed at the site of attachment. It is necessary for the nutrition of the fertilized egg with useful substances from the mother"s blood. The placenta appears in its place a little later. But up to 12-13 weeks, we are talking specifically about the chorion, since the placenta is still only forming and does not function.

If the implantation process was successful, the fertilized egg is fixed in the uterine fundus, or upper part of the organ. The blastocyst may descend into the lower uterine segment if it was unable to implant in the upper or middle part of the uterus due to some pathological reason. The chorion will then form low. The chorion’s previa is where it is in relation to the cervical canal, a narrow passageway inside the cervix that joins the vagina and the uterine cavity. Presentations are not limited to situations where the chorion has developed in the uterus’s middle or near its fundus (in the uterus’s body).

Classification

• Marginal presentation of the chorion — ​​the chorion is located low, its edge slightly touches the area of ​​the cervical canal with one edge. Such presentation is considered the most favorable, in terms of prognosis for further pregnancy and childbirth.
• Incomplete presentation — ​​the chorion is located low and covers the entrance to the cervical canal by about two-thirds. Prognosis is less optimistic, since such a position of the chorion in the uterus increases the likelihood of miscarriage or bleeding due to detachment of the chorion.
• Complete presentation — ​​the chorion has formed low and completely covers the entrance to the cervical canal. This is a rather dangerous pathology, the prognosis for which is very unfavorable.

There is a risk of miscarriage and Horion detachment with any presentation of Horion, but particularly with complete and incomplete presentations. A network of blood vessels will grow in the place of the placenta, and this is dangerous if the vessels grow in the lower part of the uterus, which by natural laws should open and release the baby when the time for delivery comes.

It is frequently the case that the presentation of the chorion progresses into another pathological state; in such case, the presentation of the placenta and subsequent spontaneous birth will probably not be permitted. The woman will have a cesarean section performed on her. Additionally, it will be difficult to deliver the baby before the due date because of the low-lying and close proximity to the placenta’s uterine exit, which increases the possibility of spontaneous bleeding at any time.

Less oxygen and nutrition will be given to the baby in the presentation, which increases the risk of hypotrophy and hypoxia.

Causes and symptoms

Internal conditions that hindered the fertilized egg from implanting normally and in a more appropriate uterine fundus are the primary cause of marginal presentation. Endometrial disorders are among these prerequisites. It is typically seen in women who have had multiple abortions or diagnostic curettage.

The chance of the fertilized egg being placed abnormally is also increased in women with a history of miscarriages and frozen pregnancies. A scar, or scars, from prior surgeries or cesarean sections on the uterus may also be a barrier to full implantation.

Reproductive organs are not known for having strong and elastic muscle tissues, and women who have given birth frequently are more likely to experience low placentation during their subsequent pregnancy.

The blastocyst is compelled to descend in search of a "shelter" in the lower uterine segment due to obstructions caused by myoma, fibroids, and other formations in the upper portion of the uterus. An uterine structure congenital anomaly, such as a bicornuate or saddle-shaped uterus, could also be the cause. There is a known sequence in which these pathologies occur: if a woman had poor placentation in a prior pregnancy, there is a strong likelihood that the fetus will attach poorly and that the chorion will not develop properly in the subsequent pregnancy.

In the early stages, there might not be any symptoms of marginal presentation of the chorion, but there might be a tiny, transient bloody discharge. They are typically correctly perceived by the woman as a threat to the child’s survival.

Such bleeding, which is caused by the uterine walls stretching and rupturing small blood vessels, can occur repeatedly in some cases—even up until the time of birth—if the placenta and chorion do not migrate. They cause the woman to become anemic, have a chronic iron deficiency, and have low hemoglobin levels in her blood. Nevertheless, the expectant mother needs to call an ambulance right away if she has bloody discharge coming from her genital tract.

Up to 90% of all babies growing in the mother’s womb against the backdrop of marginal presentation of the placenta, chorion, and even the umbilical cord can be saved with prompt hospitalization and conservative treatment.

What to do?

As previously stated, up to 12 weeks of pregnancy, 4–5% of pregnant women have a diagnosis of marginal presentation of the chorion. Not all of them, though, instantly fit the criteria for being on the patient lists for scheduled cesarean sections or the risk group. The prognosis is good, and in 90% of cases, the placenta forms in the chorion’s place and migrates higher in tandem with the uterus’s growth.

The fetus is developing quickly inside the mother’s body. The ligamentous apparatus and uterine walls are compelled to expand in order to accommodate the body’s comfort needs. The placenta, which was only partially visible at the start of the pregnancy, will "crawl" up with them. Whether the placenta migrates along the uterine wall’s anterior or posterior wall is irrelevant. It’s crucial that in the majority of cases, it actually rises and that there are no longer any dangers or threats related to low placentation.

Medicine cannot influence the migration process, speed it up or stimulate it. A woman diagnosed with “marginal presentation of the chorion” needs to follow all the recommendations of her doctor, exclude physical activity, lifting weights, jumping, sudden movements, squats. She will have to visit her doctor more often, do an ultrasound to track the process of migration of the chorion (placenta). Sex with marginal presentation is prohibited, since orgasm associated with the contraction of the uterine muscles can contribute to rapid traumatic detachment of the chorion and the occurrence of severe bleeding, in which the child can die in utero, and the woman can lose a lot of blood and die from this.

The placental migration process typically ends by the eighteenth or twentieth week of pregnancy. The real situation emerges at this point or a little later (by 35–28 weeks); if the placenta has risen, the restrictions will be removed; if not, the expectant mother will be placed in the premature birth risk group and will be monitored closely and with more anxiety going forward.

When the placenta is positioned in close proximity to or touches the internal opening of the cervix during pregnancy, this is known as marginal presentation of the chorion. Complications from this illness may include bleeding and an increased chance of preterm birth. Pregnant women should be aware of this condition because it may call for extra care and monitoring to protect the mother’s and the child’s health.

Treatment

Although the migration cannot be accelerated, a woman who exhibits only a slight chorion presentation will almost certainly be prescribed medication. The goal will be to relax the uterine muscles rather than target the chorion itself, in order to prevent further detachments and bleeding. Treatment can be administered in a hospital, depending on the severity of the presentation, or they may let you take the prescribed drugs at home. The doctor defers to his judgment on this matter.

The woman is demonstrated total sexual and psychological rest, as well as bed or semi-bed rest. The antispasmodics "Papaverine" and "No-shpa," hemostatics "Dicynone," vitamins of group B, "Magne B 6," and vitamin E in high dosages are among the drugs that are thought to be effective.

A woman is given magnesium and novocaine in the hospital; hormonal medications, such as "Duphaston," are frequently advised for her at home, but only in cases where it is established that the woman lacks specific pregnancy hormones.

It is advised to use medications like "Curantil" and "Actovegin" that enhance uteroplacental blood flow for the baby’s improved nutrition. Medication needs to be taken on a regular basis, without being skipped or forgotten.

Treatment regimens are typically fairly lengthy, lasting until an ultrasound confirms that the placenta has risen and poses no further risk, or until delivery itself if the placenta does not continue to rise higher.

Although there may be some concerns when a woman has marginal presentation of the chorion during her pregnancy, many go on to have healthy pregnancies with the right care and ongoing monitoring. This condition arises when the placenta’s edge is covering or close to the cervix, and it can occasionally cause complications.

If this condition is diagnosed in expectant mothers, it is critical that they maintain regular communication with their healthcare provider. Frequent check-ups and ultrasounds contribute to the early detection and effective management of any potential problems.

Most of the time, as the pregnancy goes on, the placenta may separate from the cervix more, which lowers the possibility of problems. Maintaining knowledge and heeding medical advice can have a big impact on making sure the mother and unborn child stay healthy during pregnancy.

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