The TAPS Trial;Fetoscopic Laser Surgery for Twin Anemia Polycythemia Sequence: a multicenter open label randomized controlled trial

Monochorionic twins share one placenta and are connected to each other via
vascular anastomoses at the placental surface, allowing the blood to transfer
bi-directionally between the two fetuses. Unbalanced inter-twin blood
transfusion can result in twin anemia-polycythemia sequence (TAPS). Management
options include: fetoscopic laser surgery, intrauterine blood transfusion (IUT)
with or without partial exchange transfusion (PET), preterm delivery, selective
feticide and expectant management. The optimal treatment for TAPS is not clear.
Fetoscopic laser surgery is the only causative treatment option, but data on
the feasibility of this procedure are mainly based on case reports and small
cohort studies. A large randomized controlled trial is needed to evaluate the
possible beneficial effect of fetoscopic laser surgery and to determine the
optimal treatment option for TAPS.

The aim of this trial is to investigate whether fetoscopic laser surgery
improves the outcome for TAPS twins as compared to the control group (standard
care consisting of expectant management, IUT, preterm delivery). The hypothesis
is that fetoscopic laser therapy will improve neonatal outcome by prolonging
pregnancy.

International multi-centered open-label randomized controlled trial to assess
whether fetoscopic laser surgery (experimental group) improves the outcome of
TAPS twins compared to standard care (control group).

In the experimental group fetoscopic laser surgery is performed, whereas the
control group is treated with standard care (expectant management, IUT (with
PET), selective feticide and/or preterm delivery, depending on the opinion of
the fetal surgeon).

Fetoscopic laser surgery is performed for several decades now and is considered
the golden standard for another feto-fetal transfusion syndrome, namely
twin-twin transfusion syndrome. Although fetoscopic laser surgery is
associated with a higher risk on several complications (including single or
double intrauterine fetal demise, iatrogenic monoamniocity, amnion
dehiscention, intra-uterine infection and preterm premature rupture of the
membranes), the natural course of TAPS on itself is characterized by high rates
of morbidity and mortality as well. The additional risk of fetoscopic laser
treatment on top of the risks that are already associated with the natural
course of TAPS is therefore estimated as low. The benefit of participating is
that TAPS twins allocated to the fetoscopic laser surgery group might be born
at a higher gestational age and therefore have a better neonatal outcome.