Fetofetal Transfusion Syndrome: Causes, Symptoms & Treatment

Fetofetal transfusion syndrome is a form of deficient blood supply that can be caused in identical monochorial twin pregnancies by anastomoses on the placenta. One of the twins receives more blood than the other. If left untreated, the syndrome usually leads to the death of both twins.

What is fetofetal transfusion syndrome?

The disease group of transplacental transfusion syndromes includes various diseases of the fetus that are due to placental insufficiency. One disease in this group is fetofetal transfusion syndrome, also known as twin syndrome. Like all other syndromes in the disease group, this syndrome is based on deficient perfusion with resulting malnutrition. Fetofetal transfusion syndrome is relatively rare but usually severe in its manifestation. Only twin fetuses are affected. The syndrome occurs in about twelve out of every 100 pregnancies with identical twins. A Canadian study gives a prevalence of 48 affected among 142,715 newborns. In monozygotic twins, there is a connection of fetal blood circulation and their vessels on the placenta. Therefore, an imbalance in blood exchange may occur between the unborn children, causing the individual symptoms of fetofetal transfusion syndrome.

Causes

Fetofetal transfusion syndrome refers only to identical twin pregnancies, during which the unborn children share the same placenta. These pregnancies are also referred to as monochorial twin pregnancies. In a large number of cases, blood vessel anastomoses form in the placenta during these pregnancies. These connections between two arteries, two veins or arteries and veins gives rise to a placenta with communicating blood systems. The transfusion of blood occurs reciprocally through the anastomoses of the placenta. Usually, this type of blood exchange does not lead to complications, as the exchange between the fetuses is normally balanced. However, if the blood exchange is unbalanced, one of the twin fetuses will lose blood to his sibling. If he loses more blood than he receives, an imbalance in blood circulation occurs. In the situation described, one twin is the donor twin. The other is the recipient twin.

Symptoms, complaints, and signs

In FFTS, symptoms usually show up on ultrasound. Nonspecific complaints such as polyhydramnios occur as the syndrome progresses. A large disparity in amniotic fluid volume is present between the two twins. Often the urinary bladder of the donor twin cannot be imaged sonographically. Doppler ultrasound shows absent or negative end-diastolic blood flow. Decompensation of the heart may also be evident during the course. The recipient twin is much larger than the donor and produces increased amniotic fluid, resulting in the development of polyhydramnios. This symptom is often associated with uterine overdistension, which can result in premature labor or premature rupture of the amniotic sac. Because of the increased blood volume, the recipient twin often develops heart failure or generalized edema. The donor twin is significantly smaller than the recipient because of malnutrition. Amniotic fluid decreases in his amniotic cavity. After birth, the donor suffers from anemia. Both the donor and the recipient may die if TTTS is left untreated. If one of the two fetuses dies, the second bleeds to death because of the anastomoses in about one-third of cases.

Diagnosis

The first step in diagnosing fetofetal transfusion syndrome is to establish that a monochorial twin pregnancy is present. Choriality is ideally checked between the ninth and twelfth weeks of gestation. Monochorial twin pregnancies are monitored closely by sonography approximately every third week. Differentially, the physician must rule out placental insufficiency at diagnosis. In the case of insufficiency, the larger fetus would not have a large increase in amniotic fluid. If left untreated, fetofetal transfusion syndrome results in premature birth and nearly 100 percent infant death. If the risk is recognized and treated early enough, the prognosis is somewhat more favorable.Permanent impairment is a common consequence of survival-based treatments.

When should you see a doctor?

In any case, treatment must take place for this syndrome. If there is no treatment or only delayed treatment, both children usually die from this disease. In most cases, the disease can be diagnosed directly before birth during check-ups. For this reason, pregnant women should regularly attend such examinations to avoid such complications. If one fetus dies due to the syndrome, the other usually dies as well due to the lack of blood supply. If the syndrome is detected, immediate treatment is necessary in this case. Diagnosis and treatment can be done at a gynecologist or in a hospital. Furthermore, a doctor must also be consulted if the patient suffers from premature onset of labor. In that case, the hospital should be visited directly. In emergencies, the emergency doctor should be called. The success of the treatment strongly depends on the severity and on the time of the diagnosis, so unfortunately a general prediction cannot be given. If diagnosed early, no particular compilations usually occur.

Treatment and therapy

To date, no treatment methods exist for fetofetal transfusion syndrome that ensure infant survival with certainty. If symptoms are mild, treatment is often a wait-and-see approach. If symptoms worsen, amniocentesis is usually used first. The amniotic sac of the recipient is punctured. The resulting drainage results in relief. The amniotic sac does not break and premature labor does not occur. This symptomatic treatment remedies only part of the sequelae, since polyhydramnios may develop again after the puncture. Another treatment option is laser ablation. In this procedure, the vascular anastomoses are cut by laser and are the treatment of choice for pronounced fetofetal transfusion syndromes. The ablation is preceded by a reflection of the amniotic sac, which makes the vascular connections detectable and precisely treatable with the laser. The vessels close and two fully separated circuits are present. This causal treatment eliminates the cause of the symptoms. Depending on the formation of the placenta, complications may arise during this treatment. For example, it is conceivable that one of the twins does not have enough placenta after the separation. In this case, the twin dies. However, the second twin usually survives and remains unaffected by the death of the other because of the separate circuits. Fetuscopy can also promote other complications, such as premature rupture of the membranes or hemorrhage.

Outlook and prognosis

The prognosis of fetofetal transfusion syndrome is difficult to assess. However, without the use of an experienced medical team, it is unfavorable. According to current medical knowledge, the condition cannot be adequately treated by physicians due to a lack of options. To date, the syndrome can take a fatal course. Initially, the development of identical twins in the womb is monitored and observed by doctors. If no serious complications occur, there is no further intervention in the growth process. In a large number of cases the prognosis is good. They give birth without any other abnormalities or peculiarities. Nevertheless, disturbances such as sudden bleeding or rupture of the bladder occur very frequently during pregnancy. In these cases, immediate intervention of doctors is necessary. Depending on the progress of the pregnancy, a premature birth is induced. The goal is to ensure the survival of the fetuses. Often, in fetofetal transfusion syndrome, the death of one twin occurs despite all efforts. Death of both twins is also possible. If the circulation cannot be stabilized and thus the growing organism cannot be adequately supplied with blood, the prospect of a good prognosis decreases. The chances of recovery increase if the expectant mother seeks care from a well-trained birthing center.

Prevention

Fetofetal transfusion syndrome cannot be prevented. However, treatment at an experienced center can prevent fetal death.

Aftercare

In transfusion syndrome, there are usually no special or direct measures and possibilities of aftercare available to those affected. In most cases, this syndrome unfortunately leads to the death of both children, so that in this case no further aftercare can be provided to keep the children alive. The aftercare itself is usually based on the psychological condition of the parents and is intended to prevent psychological upsets or depression. As a rule, the parents affected by transfusion syndrome rely on the help and support of friends and family to prevent such psychological upsets. However, a visit to a professional psychologist can also be very useful. Also the contact to other affected parents of the transfusion syndrome proves to be very often useful. If the transfusion syndrome does not cause the death of the two children, they usually need intensive care. However, it is not uncommon for only one of the two children to survive such care. As a rule, the health of the mother is not negatively affected by the transfusion syndrome, so that there is also no reduced life expectancy for her.

What you can do yourself

Expectant mothers should participate in all offered control and preventive examinations during pregnancy to protect their own lives as well as those of their offspring. In these examinations, diseases are detected and can be treated. In the case of fetofetal transfusion syndrome, the natural healing powers do not lead to relief of symptoms. Rather, the death of a fetus occurs in a twin pregnancy. Therefore, the self-help measures in this condition lie in the participation of the examinations during an existing pregnancy. If the expectant mother notices sudden irregularities despite all the checks and clarifications, she should immediately consult a doctor. This also applies if there is a diffuse feeling that something might be wrong with the unborn children. The pregnant woman should trust her perception and intuition and not be irritated by other people or influences. For the protection of the mother as well as the fetuses, it is advisable to consult a doctor again in case of suspicion. In addition, the pregnant woman will help herself and her unborn twins if she remains calm throughout the treatment period and does not fall into anxious or panicky behavior. Unnecessary excitement should be avoided, as this can place additional demands on the entire circulatory system as well as the blood flow and throw it out of balance.