Doppler Ultrasonography of the Umbilical Cord in Complicated Pregnancies

Ninety-two gravid women had Doppler insonation of the umbilical cord after diagnosis of various pregnancy complications. Calculations of the systolic-diastolic (S/D) ratio were plotted against a nomogram of values developed at the Hospital of the University of Pennsylvania. An S/D ratio greater than the 95th percentile for gestational age correctly predicted 58% of women who became preeclamptic and 61% of infants who were small for gestational age (SGA). Of those fetuses with an elevated S/D ratio, 42% suffered fetal distress as defined by an abnormal fetal heart rate tracing, a 1- or 5-minute Apgar score less than 5 or 7, respectively, or a cord blood pH determination less than 7.20; 60% required operative delivery; and 49% stayed in the hospital longer than 5 days or were admitted to the Neonatal Intensive Care Unit (NICU). All these values are significantly greater than those obtained in a control group of uncomplicated pregnancies or a group of women with similar pregnancies, but with normal measurements of the umbilical artery S/D ratio. Moreover, 69% of abnormally elevated umbilical artery S/D ratios were detected at or before 30 weeks' gestation. Calculation of an S/D ratio of the umbilical cord greater than the 95th percentile for gestational age is an early and sensitive predictor of poor perinatal outcome.