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Iona Millais: Twin-to-Twin Transfusion Syndrome

Monochorionic (MC) twins are identical twins that share the same placenta.  Such twinning carries a hugely increased risk of intra-uterine growth restriction, brain injury and fetal death. The principle reason for the higher risks associated with monochorionicity is the presence of inter-twin vascular connections (anastomoses). If the blood movement which is delicately balanced by these placental anastomoses is upset over a prolonged period of time, it results in twin-twin transfusion syndrome (TTTS).  The key to managing TTTS is appropriate antenatal monitoring. 
TTTS complicates 10-15% of MC twin pregnancies. Presentation is usually in the second trimester where a scan shows different amniotic fluid volumes surrounding each twin. The recipient twin will be larger and have excessive amniotic fluid whilst the donor twin will appear enshrouded within its amniotic membrane and is often described as the "stuck" twin.
Untreated, perinatal mortality exceeds 80%. There is also significant risk of brain injury arising from pre-term delivery of any surviving. Treatment options include serial amnioreduction, septostomy, selective fetocide and laser ablation. The treatment of choice, particularly for severe disease is laser ablation in which the causative anastomoses on the shared placenta are identified and destroyed using a laser. TTTS is staged from stage I to stage V.
I am instructed on two TTTS cases. The first of which, the Trust failed to offer fortnightly scans from 20 weeks. This meant that the condition was not picked up until she had reached stage IV and she too far along to undergo laser ablation. Tragically one of her twins died and the other has suffered a brain injury from being delivered prematurely. In the other case, the condition was picked up early enough in her pregnancy for her to undergo laser ablation, but unfortunately the condition was too advanced for treatment to save one of her twins. I hope to recover damages in both these deserving cases.
Recommended antenatal monitoring of twins
•         All twins should be scanned in the first trimester and offered screening for aneuploidy by nuchal translucency measurement at this stage. Early ultrasound is recommended to determine whether twins are mono or di-chorionic.
•         MC twins should have a scan at 16 weeks in order to detect early signs of TTTS.
•         All twins should be offered an anomaly scan at 20 weeks.
•         Thereafter MC are seen fortnightly until delivery (DC twins need only be monitored monthly).
If you are pregnant with twins, I would urge you to ensure that appropriate antenatal screening is in place. If you are in the unfortunate position where TTTS was not detected early enough during your pregnancy, please contact the RJW team to investigate whether you have a claim.Iona Millais is a solicitor specialising in clinical negligence. If you or a member of your family have a clinical negligence enquiry please call our expert clinical negligence solicitors on 0800 916 9049, fill in our short online claim form or email and one of our specialist clinical negligence team will be in touch.