Limitations of ultrasound in diagnosing intrauterine growth restriction in severe preeclampsia

Objective.The objective of this study was to determine test characteristics of ultrasound in detecting intrauterine growth restriction (IUGR) in severe preeclampsia (S-PEC). Study design.We performed a prospective study (2005-2007) to evaluate risk factors for PEC. Women with severe PEC and an ultrasound ≤3 weeks of delivery were enrolled. Chi square analysis determined associations between diagnosis of IUGR and small for gestational age (SGA) birth weight. Multivariable logistic regression was used to control for confounders. Fetal growth rate and test characteristics of ultrasound were calculated. Results.Ninety-three patients were enrolled. There was a significant association between IUGR and SGA, but no association between maternal demographic factors and IUGR. Test characteristics of ultrasound to diagnose IUGR in severe PEC were: sensitivity 56.7%, specificity 93.7%, PPV 81.0%, NPV 81.9%. The positive likelihood ratio(+LR) for ultrasound to detect IUGR in severe PEC was 8.9. Conclusion.Current ultrasound practice has moderately good positive and negative predictive values and a high specificity for the diagnosis of IUGR in women with severe PEC. However, the poor sensitivity and low+LR indicate that additional modalities are needed to improve the usefulness of ultrasound in detecting IUGR in severe PEC.