Fibronectin as prodictor of preterm labour in monochorionc twins treated with fetoscopic laser surgery

Twin to twin transfusion syndrome (TTTS) is a condition in which blood from one
twin (the donor) is transfused into the other twin (the recipient) via blood
vessels in their common placenta. It occurs in 15% of identical twins that
share a placenta (about two percent of all twin pregnancies). It has
potentially serious and life threatening effects upon both twins.
Normally, identical monochorionic twins have blood vessels that connect to each
other on the surface of the placenta. Blood can flow from one twin to the other
but this flow is balanced in both directions. TTTS occurs when there is a
disturbance to this balance and there is a "net" flow of blood from the donor
to the recipient twin. The donor twin decreases the amount of amniotic fluid
and the recipient twin gets too much amniotic fluid and often gets heart
problems. The best available treatment for TTS is fetoscopic laser surgery. The
aim of the fetoscopic laser treatment is to interrupt the inter-twin
circulation through coagulation of the vascular anastomoses on the placental
surface. The fetoscope is 3mm thick and has to pass the uterus wall and the
membranes to reach the placental surface. The risk of rupture of membranes
after laser treatment is 10%. It's very important to predict and detect preterm
labour in an early stage. Fetal fibronectine proved to be a good marker for
preterm labour in singletons but is never tested in monochorionic twins treated
for TTTS

To determine whether fFN kan detect preterm delivery in monochorionic twins
treated for TTTS.

Prospective trial.

Time scedule:

Before procedure:
• Fibronectin swab
• Vaginal swab (culture)
• Cervixlengte meassurement
• Bloodsample (7ml)

During procedure, 15ml amniotic fluid (which will be drained to reduce the
polyhydramnios):
• 5 ml PCR
• 5 ml Luminex (cytokine assay)
• 5 ml culture

1 day after procedure:
• Fibronectin swab

After delivery:
• A part of the amnion and umbilical cord will be send to the department of
pathology to investigate whether there are signs of chorioamnionitis and/or
funniculitis

Treatment and follow-up of all TTTS patients are according to standardized
care. There will be two extra examinations, before and one day after treatment.