Authors: Nadia Bardien1,5, Clare L. Whitehead1,3, Stephen Tong1,3, Antony Ugoni4, Susan McDonald5, Susan P. Walker1,2*
1 Department of Perinatal Medicine, Mercy Hospital for Women, Melbourne, Australia, 2 Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, Australia, 3 Translational Obstetrics Group, University of Melbourne, Melbourne, Australia, 4 School of Physiotherapy, University of Melbourne, Melbourne, Victoria, Australia, 5 La Trobe University, Mercy Hospital for Women, Melbourne, Australia
To determine whether fetuses that slow in growth but are then born appropriate for gestational age (AGA, birthweight >10th centile) demonstrate ultrasound and clinical evidence of placental insufficiency.
Prospective longitudinal study of 48 pregnancies reaching term and a birthweight >10th cen-tile. We estimated fetal weight by ultrasound at 28 and 36 weeks, and recorded birthweight to determine the relative change in customised weight across two time points: 28–36 weeks and 28 weeks-birth. The relative change in weight centiles were correlated with fetoplacental Doppler findings performed at 36 weeks. We also examined whether a decline in growth trajectory in fetuses born AGA was associated with operative deliveries performed for suspected intrapartum compromise.
The middle cerebral artery pulsatility index (MCA-PI) showed a linear association with fetal growth trajectory. Lower MCA-PI readings (reflecting greater diversion of blood supply to the brain) were significantly associated with a decline in fetal growth, both between 28–36 weeks (p = 0.02), and 28 weeks-birth (p = 0.0002). The MCA-PI at 36 weeks was significantly higher among those with a relative weight centile fall <20%, compared to those with a moderate centile fall of 20–30% (mean MCA-PI 1.94 vs 1.61; p<0.05), or severe centile fall of >30% (mean MCA-PI 1.94 vs 1.56; p<0.01). Of 43 who labored, operative delivery for suspected intrapartum fetal compromise was required in 12 cases; 9/18 (50%) cases where growth slowed, and 3/25 (12%) where growth trajectory was maintained (p = 0.01).
Slowing in growth across the third trimester among fetuses subsequently born AGA was associated with ultrasound and clinical features of placental insufficiency. Such fetuses may represent an under-recognised cohort at increased risk of stillbirth.
Published in PLOS One: DOI:10.1371/journal.pone.0142788