Non-immune hydrops fetalis

M R C O G PA R T 2 · S O S P O C K E T C A R D · K N O W L E D G E A R E A 5 – A N T E N ATA L C A R E

Non-Immune Hydrops Fetalis: A Practical Guide for Obstetricians Khairudin D et al. Non-immune hydrops fetalis: a practical guide for obstetricians. TOG 2023;25:110–120. doi:10.1111/tog.12862

1:2000 >90% 60% PREGNANCIES AFFECTED BY NIHF OF HYDROPS FETALIS IS NON-IMMUNE CAUSE FOUND PRENATALLY (+29% WITH ES)

DO N' T-M IS S FA C TS

  1. HF diagnosis needs ≥2 fluid compartments; organ-fluid findings (e.g. hydronephrosis, ventriculomegaly) do not count

  2. NIHF = >90% of hydrops; affects 1:2000 pregnancies; up to 60% perinatal mortality

  3. ES adds ~30% diagnostic yield after normal CMA – part of NHS England R21 pathway

  4. MCA PSV >1.5 MoM → FBS to confirm/treat fetal anaemia; 2nd/3rd trimester HF = fetal medicine emergency, tertiary review within 24h

  5. Termination under Ground E; feticide advised >21+6 weeks

  6. Maternal mirror syndrome = pre-eclampsia-like picture + anaemia/haemodilution (not haemoconcentration); resolves only with delivery/NIHF resolution

  7. Deliver from 34 weeks (steroids if worsening) or term 37–38 weeks if stable, in a level III neonatal unit

  8. Placental thickness ≥5 cm = placentomegaly; ‘ground glass’ appearance may indicate chorangioma

CAUSE BY TRIMESTER (DOMINANT)

1st: chromosomal (70%) 2nd: chromosomal 20% + monogenic (ES: up to 40%), infection 20%

3rd: genetic up to 25% (mostly monogenic), cardiovascular up to 25%

ABBREVIATION KEY

NIHF — non-immune hydrops fetalis sFlt-1 — soluble FMS-like tyrosine kinase 1

HF — hydrops fetalis GGT — gamma glutamyl transferase

CMA — chromosomal microarray analysis UA PI — umbilical artery pulsatility index

ES — exome sequencing TTTS — twin-twin transfusion syndrome

PCR — polymerase chain reaction TAPS — twin anaemia polycythaemia sequence

CVS — chorionic villus sampling TRAP — twin reversed arterial perfusion sequence

FBS — fetal blood sampling HLHS — hypoplastic left heart syndrome

MCA PSV — middle cerebral artery peak systolic velocity SVT — supraventricular tachycardia

MoM — multiples of the median CPAM — congenital pulmonary airway malformation

MDT — multidisciplinary team BPS — bronchopulmonary sequestration

CMV — cytomegalovirus EXIT — ex utero intrapartum treatment

PlGF — placental growth factor CTG — cardiotocography

Source: The Obstetrician & Gynaecologist (TOG), RCOG journal — doi:10.1111/tog.12862

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