Delivery of the growth-restricted preterm fetus.

www.thelancet.com Published online March 5, 2015 http://dx.doi.org/10.1016/S0140-6736(14)62455-7 1 Stillbirth, neonatal death, and neurodevelopmental abnorm alities are signifi cantly more common in growth restricted fetuses than in those with normal growth. Health care for women with pregnancies complicated by preterm fetal growth restriction needs complex assessment and planning, including the ability to diff erentiate the constitutionally small fetus from the pathologically small fetus; determine the cause of small fetal size; manage common maternal comorbidities; and decide when to deliver a growth restricted fetus to maximise chances for survival and minimise maternal risk. Fetal growth restriction is defi ned diff erently by various organisations and authors. In a survey of Irish obstetricians and trainees, more than 30 diff erent defi nitions of fetal growth restriction were identifi ed. Fetal size below the tenth percentile, a common defi nition, can be the result of familial traits (ie, the constitutionally small fetus), intrinsic fetal abnormalities (eg, fetal alcohol syndrome or aneuploidy), or uteroplacental abnormalities. For individuals with uteroplacental abnormalities, the timing of delivery based on ongoing assessment of maternal and fetal wellbeing is crucial. The dominant theory is that, at some point, the fetal side of an abnormal placenta will be so resistant to perfusion that the fetus will adapt, increasing rightsided heart pressures, which will result in increased fl ow pulsatility in the ductus venosus (DV), ultimately to the point that loss of the A wave during pulsed Doppler interrogation of the DV occurs. The fetus might retain normal oxygenation to a point, as shown by normal fetal heart rate tracing, but ultimately becomes acidotic and hypoxic. At what point along this pathway should the fetus be delivered to decrease the risk of brain injury and death? In The Lancet, Christoph Lees and colleagues report the results of the Trial of Umbilical and Fetal Flow in Europe (TRUFFLE) to address this question. Fetal growth restriction was defi ned as a fetal abdominal circumference lower than the tenth percentile and abnormal umbilical artery Doppler with a pulsatility index of more than the 95th percentile, with or without reversed or absent end-diastolic fl ow. With these inclusion criteria, the study group is enriched with participants with placental disease as the likely cause of fetal growth restriction. In TRUFFLE, 503 women were randomly assigned to one of three groups for timing of delivery: abnormal variability on cardiotocography based on computerised interpretation (166 women), DV resistance index greater than the 95th percentile (DV p95; 167 women), and DV with no A wave (DV no A; 170 women). Safety net criteria were described by which delivery was indicated irrespective of randomised group. The primary outcome was survival without neurodevelopmental impairment at 2 years. Comprehensive standardised neurodevelopmental assessments at 2 years, corrected for prematurity, were done by trained psychologists or paediatricians masked to study group. TRUFFLE is one of few studies to examine long-term outcomes in growth restricted fetuses. The growth restriction intervention trial (GRIT) randomly assigned patients to early or delayed delivery when evidence of fetal compromise was present, but the obstetrician was in equipoise regarding whether delivery was indicated. Neonatal outcomes, childhood morbidity at 2 years, and morbidity at school age did not diff er between groups in GRIT, which did not help clinicians with regard to timing of delivery in growth restricted fetuses. The proportions of infants in TRUFFLE who survived without neurodevelopmental impairment in those randomly assigned to delivery in the cardiotocography short-term variation (CTG STV; 111 [77%] infants of 144 with known outcome, 95% CI 70–83), DV Delivery of the growth restricted preterm fetus