Treatment of twin-to-twin transfusion syndrome

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The natural outcome of twin-to-twin transfusion syndrome involves high in utero or neonatal morbidity and mortality rates in the majority of cases; the incidence of neurological disability is 40–80% and the rate of mortality is almost 100% in cases that develop before week 20 and 80% if the onset is between weeks 21 and 26.

Early diagnosis and timely treatment are key factors in improving the prognosis. The condition requires urgent treatment, within a few days of the diagnosis, because it can worsen very quickly.

The first-choice treatment for severe cases of twin-to-twin transfusion syndrome is a surgical intervention: foetoscopic laser surgery.

Foetal surgery (foetoscopy) is the treatment of choice in twin-to-twin transfusion syndrome. It was proposed as a treatment for TTTS at the beginning of the 1990s.

Foetoscopic laser surgery is a minimally invasive procedure. A 3 mm incision is made in the skin and then a cannula (trocar) equipped with a camera and fibre optic cable is inserted into the uterine cavity.

Twin-to-twin transfusion syndrome is a problem associated with the placenta, not the foetuses, and so the treatment is also focused on the placenta. An endoscope provides a direct view of the placenta and is used to identify the interconnecting blood vessels which are subsequently coagulated with a laser. The aim is to eliminate all the vascular connections between the two foetuses and divide the single placenta into two independent placental territories, as if it were a dichorionic pregnancy.

This intervention is usually performed under local anaesthesia with sedation so that the expectant mother is more relaxed. She will be asleep but breathing spontaneously.

Patients must adhere to total bed rest for the first 24 hours after the procedure. The first ultrasound control is taken after 24 hours and so long as there are no complications the patient can start moving around and will be discharged to their home.

Patients attend weekly ultrasound check-ups in the weeks following the intervention and are indicated relative rest and sick leave until the end of the pregnancy. Relative rest means avoiding pressure on the abdomen (do not lift heavy objects or carry out any exercises that increase abdominal pressure) and being active for short periods but frequently (moving around the house, walking for 5–10 minutes).

A second-choice treatment is that of amniodrainage. Amniodrainage consists of introducing a needle into the amniotic cavity to extract the excess fluid from the recipient’s amniotic sac and therefore reduce the pressure and the risk of a preterm birth.

The results of amniodrainage are evidently inferior to those of foetoscopic laser surgery and so it is only used in cases where the latter is either impossible or contraindicated.

The mean survival achieved through this method is close to 60% and the rates of neurological disability are higher than those observed with laser treatment. Amniodrainage manages to extend the pregnancy but it is only a symptomatic treatment and does not deal with the cause of the disease – the transfusion of blood across the aforementioned anastomoses.

Substantiated information by:

Mar Bennasar Sans
María Marí Guasch

Published: 20 February 2018
Updated: 8 July 2025

The donations that can be done through this webpage are exclusively for the benefit of Hospital Clínic of Barcelona through Fundació Clínic per a la Recerca Biomèdica and not for BBVA Foundation, entity that collaborates with the project of PortalClínic.

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