The National Institute for Health and Clinical Excellence (NICE) has issued full guidance to the NHS in England, Wales, Scotland and Northern Ireland on intrauterine laser ablation of placental vessels for the treatment of twin-to-twin transfusion syndrome.


Twin-to-twin transfusion syndrome occurs when unborn identical twins have different sacs in the womb but share the same placenta. This results in blood flow from one twin to the other through connections between blood vessels in the shared placenta becoming unbalanced. The volume of fluid around the twins also becomes uneven. This procedure is performed under regional analagesia or local anaesthesia with maternal sedation. Under ultrasound guidance, a cannula and needle are inserted through the maternal abdominal wall, uterine wall and into the amniotic sac of the recipient twin. The needle is removed, and a fetoscope with a thin fibre to carry the laser energy is then inserted through the cannula. The fetoscope is used to look at the blood vessels on the surface of the placenta. Vessels that are found to communicate between the twins are then coagulated using the laser. After completion of surgery, excess amniotic fluid in the recipient twin's sac is removed to achieve a normal volume.

Coding recommendations

R07.1 Endoscopic laser ablation of placental arteriovenous anastomosis

Y53.2 Approach to organ under ultrasonic control

A code from category Y95.- Gestational age must be assigned in a subsidiary position where this information is available.