P92Early second trimester low umbilical coiling index predicts small for gestational age fetuses

Abstract

Objective To evaluate the role of early second trimester Doppler velocimetric studies, umbilical coiling index and umbilical cord cross‐sectional area as a test for the prediction of small for gestational age (SGA) infants. Study design Doppler blood flow studies in 147 singleton pregnancies at risk for delivery of a SGA newborn were performed at 15 ± 1 weeks of gestation from umbilical artery, middle cerebral artery, inferior vena cava and ductus venosus. Pulsatility index (PI) values were calculated for the arteries and preload index (PLI) and S/A values for the veins. The sonographic cross‐sectional area of the umbilical cord was measured in a plane adjacent to the insertion into the fetal abdomen. The umbilical coiling index was calculated using sonographic longitudinal views of cord vessels from several segments antenatally. SGA newborn was identified when the birth weight was below the 10th percentile for gestational age. Results Among 147 pregnancies studied, 124 fulfilled the study criteria. 39 of the fetuses were SGA at birth (31.5%). The mean gestational age at delivery (± SD) of the normally grown fetuses was 39.7 ± 1.28 weeks and of the SGA newborns was 34.6 ± 2.9 weeks (range 28–40 weeks). The best single predictor of a SGA infant was the coiling index with a sensitivity of 79% specificity of 86%, positive predictive value of 72% and negative predictive value of 90%. Conclusion Umbilical coiling index measured in the early 2nd trimester is useful in predicting birth of a SGA infant and may be a marker of subsequent growth restriction.