Discovering a twin pregnancy is always a surprise. Regardless of how the news is received, this type of gestation requires special monitoring, since it presents some particular risks for both the mother and babies.
Twin pregnancies are classified into two types: monocorials, when fetuses share the same placenta, and bicorials, when each one has their own. Approximately 20% of these pregnancies are monocorial and, in some cases, they can present complications such as fetal fetal transfusion syndrome, which occurs between 10% and 15% of this type’s gestations.
Fetal fetal transfusion syndrome occurs when blood flow between twins is unequal. One of the fetuses, known as a donor, receives less blood, which affects its growth and production of urine, while the other, the receiver, receives an excess, which can overload its circulatory system.
This condition is classified as Five stages (Iv) according to its severity. In the first levels (I and II), severe cardiovascular alterations are often detected. From Stage III, serious complications may appear in the cardiovascular system, and in the IV, one of the fetuses has an advanced heart failure. Stadium V means the death of one or both twins.
It is a syndrome that can take without any symptomatology in the mother
Dr. Mar Bennasar, specialist in fetal medicine of the Clinic Barcelona Hospitalwarns: “This a syndrome that can take without any symptomatology in the mother.” This represents a risk, since, if not detected in time the consequences can be serious. When there are symptoms, the most common are abdominal distension and contractions. However, being little specific, they may not immediately be associated with fetus-fetal transfusion syndrome. Therefore, as Dr. Bennasar points out, it is crucial to follow the established controls: “It is very important to perform serial controls in these gestations. Normally, we control every two weeks. ”
The diagnosis is made by ultrasound. It is detected because the donor fetus has little amniotic liquid in its bag and it is not possible to see its bladder. Instead, the receiving fetus shows a large amount of amniotic fluid and the distended bladder. Sometimes, there is also a discrepancy in the size and weight of fetuses, although alone, this difference is not enough to confirm the diagnosis. “Fetal fetal transfusion may appear at any time in pregnancy, but it is more frequent between 16 and 25 weeks,” explains Dr. Bennasar. For this reason, controls are especially important in this period of pregnancy.
Neurological disability rates associated with this disease vary between 40% and 80%. The mortality rate is around 80% of cases when the condition occurs between 21 and 26 weeks, and reaches 100% if it occurs before 20 weeks. Therefore, once diagnosed, the disease requires urgent treatment.
The first therapeutic option is surgical intervention, specifically a fetoscopy. During this procedure, an incision of about 3 millimeters is made on the skin and a cannula is inserted to the uterine cavity. With a laser, vascular connections are coagulated, through which fetuses exchange liquids, and the placenta is divided into two, similar to what would happen in a bicoral pregnancy.
Although it may seem a complex procedure, Dr. Bennasar points out that “fetoscopy is a minimally invasive technique.” After the intervention, the patient must keep absolute rest during the first 24 hours. In the following weeks, relative rest and weekly ultrasound controls are recommended.
There are other methods, although they are less effective. One of them is amniodrenaje, which consists in extracting excess amniotic fluid from the receiver’s bag. However, the survival rate with this method is 60%, so it is used only in those cases in which laser intervention is not viable.
Fetoscopy is a minimally invasive technique
Among the Complications The most frequent treatment is the breakage of the amniotic bag, which occurs by 10% -20% of cases and, generally, does not entail the loss of pregnancy. Premature delivery and gestational loss can also occur, which occurs in 5% -10% of cases. Other complications are the selective growth delay and the neurological sequelae of the surviving fetus, mainly associated with prematurity. Finally, intraamniotic infection, reverse fetal fetus transfusion and a new form of chronic fetal fetal transfusion, characterized by a hemoglobin difference between twins.
Although without treatment the mortality index is very high, the prognosis improves considerably after surgery. After the procedure, the survival of at least one fetus is reached by 85%-90%of the cases, while the survival of both fetuses is achieved in 65%. The neurological sequelae is around 5%.
Since the Causes From the fetal fetal transfusion syndrome are unknown, the current research focuses on two key areas: to improve surgical procedures to reduce complications during and after operation, and develop methods to minimize neurological and cardiovascular sequelae in the fetuses that survive Surgery
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