Identification and management of fetal anaemia

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

Identification and Management of Fetal Anaemia: A Practical Guide Castleman J et al. Identification and management of fetal anaemia: a practical guide. TOG 2021;23:196–205. doi:10.1111/tog.12740

1.5 MoM 1–3% 84% MCA-PSV ACTION LINE FOR FBS FETAL LOSS/PRETERM RISK PER IUT OVERALL SURVIVAL AFTER IUT

DO N' T-M IS S FA C TS

  1. MCA-PSV action line for considering fetal blood sampling: 1.5 MoM for gestation

  2. Severe anaemia = fHb >70 g/L below mean for gestation or <0.55 MoM

  3. Refer if anti-D >4 IU/ml, anti-c >7.5 IU/ml, anti-K as soon as detected, or any other titre ≥32; rapid rise = doubling in 14 days

  4. Anti-D extra dose within 72 hours of sensitising event; 500 IU covers 4 ml fetal RBCs (confirm with Kleihauer–Betke)

  5. Parvovirus B19: fetal loss 13% if infection <20 weeks vs 0.5% later; weekly scans 4–10 weeks post-infection

  6. IUT overall survival 84% (>90% without hydrops); complication rate 3.3%; risk of harm 1–3%, higher <20 weeks

  7. If fHb <4 g/L, avoid over-transfusion – risk of adverse haemodynamic effect and coexisting parvovirus myocarditis

  8. TAPS: spontaneous up to 5% of MCDA twins, up to 16% post-laser (reduced to 3% with Solomon technique)

DIAGNOSIS AT A GLANCE

Screen: MCA-PSV Doppler (1.5 MoM action line) Gold standard: fetal blood sampling (up to 2% loss/preterm risk)

ABBREVIATION KEY

HDFN — haemolytic disease of the fetus and newborn SCT — sacrococcygeal teratoma

fHb — fetal haemoglobin CMV — cytomegalovirus

MoM — multiples of the median G6PD — glucose-6-phosphate dehydrogenase

MCA-PSV — middle cerebral artery peak systolic velocity MRI — magnetic resonance imaging

RBC — red blood cell RCOG — Royal College of Obstetricians & Gynaecologists

IUT — intrauterine transfusion NICE — National Institute for Health and Care Excellence

IVIg — intravenous immunoglobulin PETIT — Postponing Early IUT with IVIg Treatment (study)

cffDNA — cell-free fetal DNA LOTUS — follow-up study of children after IUT

FMH — fetomaternal haemorrhage IgG/IgM — immunoglobulin G / immunoglobulin M

TAPS — twin anaemia polycythaemia sequence FcRn — neonatal Fc receptor

Source: The Obstetrician & Gynaecologist (TOG), RCOG journal — doi:10.1111/tog.12740

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