P05.10: Perinatal outcome of small for gestational age babies born after 34 weeks of gestation: role of prenatal surveillance

Objective: Cardiac disproportion often signifies important diseaseresulting in a postnatal duct-dependent circulation. Diagnostic accuracywas prospectively assessed in fetuses referredwith disproportiondetected during routine obstetric screening (1997–2002).Methods: We trained sonographers to recognise cardiac disproportionin four transverse views. Fetuses without disproportion; isolatedseptal defects, balanced atrioventricular septal defects, tetralogy ofFallot or double outlet right ventricle with large pulmonary arteries,simple transposition or moderate valvar stenosis were excluded.Results: 293/1721 cardiac referrals were for suspected cardiacsonographic anomalies, 109 had disproportion confirmed (60%left sided hypoplasia). Diagnosis included isomerism (6), persistentleft superior caval vein (LSVC) (6), chromosomal defects (15),and extracardiac malformations (25). Duct-dependent postnatalcirculation was likely in 83%.12.8% with disproportion had no important cardiac abnormality– 5 had aneuploidy, hydrops or vein of Galen aneurysm, 7 weremanaged as suspected coarctation (CoA) (3 mild arch hypoplasia(1 45XO), 4 normal). Continuous flow on colour and Doppler atthe isthmus (5) aided CoA diagnosis, but one with restrictive foramenexcluded it. LSVC occurred in 5.5% disproportion vs. 0.5%referred population (p = 0.00001). Disproportion was not confirmedin 1.5% referrals. Neonatal outcomes were confirmed in all but onethat moved abroad.Conclusions: Recognition of cardiac disproportion is a simple buteffective protocol with a low false positive referral rate (33/1721,1.9%) in second trimester screening