TTTS and monochorionic twins — natural-cause walkthrough for Babies A and B

A walkthrough of twin-twin transfusion syndrome (TTTS) and the broader monochorionic-twin pathology as the natural-cause explanation for sequential deteriorations in Babies A and B. TTTS prevalence in monochorionic twins is 10-15%, with mortality 60-100% untreated; it remains a leading cause of monochorionic-twin neonatal death even with modern management. The piece sets out why sequential deteriorations in monochorionic twins are the expected pattern when underlying placental pathology is shared — not the signature of deliberate harm. Independent paediatric review including Dr Martyn Pitman has covered the antenatal Doppler trajectory case-by-case. The Panel's findings for Babies A and B identify natural-cause mechanisms consistent with monochorionic-twin pathology and inconsistent with the prosecution's air-embolism mechanism.