Unexpected Non-immune Hydrops Foetalis With Supraventricular Tachycardia in a Premature Neonate

Hydrops foetalis (HF) refers to abnormal excessive fluid collection in foetal compartments.We present a case of unexpected non-immune HF (NIHF) in a male neonate born at 31 weeks of gestation via emergency caesarean section.He was born cyanotic with absent breathing effort and heart rate, and was noted to have generalised oedema, a tense abdomen, and a puffy chest wall consistent with HF.Following initial resuscitation and intubation, he developed supraventricular tachycardia (SVT), which was reversed following administration of three incremental doses of adenosine.Biochemical evaluation revealed significant hypoalbuminaemia, and initial blood gas showed marked acidosis.Lung ultrasound demonstrated bilateral pleural effusions, and an emergency echocardiogram showed a mild pericardial effusion with a small patent foramen ovale.After transfer to the tertiary centre, he had recurrent episodes of SVT requiring multiple doses of adenosine and initiation of propranolol and flecainide.A total of 220 mL of ascitic fluid was drained, but no pleural drain was required.He subsequently improved clinically and was discharged on maintenance amiodarone and propranolol.This case demonstrates the importance of thorough assessment in neonates with NIHF to identify potentially treatable underlying causes, such as SVT.A detailed assessment to identify underlying aetiology and complications is essential, with management guided by these findings.Early diagnosis and treatment, along with effective resuscitation, can rapidly improve haemodynamic stability and outcomes.