Uterine artery Doppler velocimetry for the detection of adverse obstetric outcomes in patients with elevated mid-trimester β-human chorionic gonadotrophin

Aim The aim of this study is to review the clinical usefulness of Doppler velocimetry of the uterine artery for the detection of adverse obstetric outcome in a population of women with elevated mid-trimester serum beta-human chorionic gonadotrophin (beta hCG). Methods Women with an unexplained elevated mid-trimester beta hCG level (>= 4.0 multiples of the median) are offered uterine artery Doppler assessment at 22-24 weeks of gestation. We have audited the clinical usefulness of this practice by reviewing the prevalence of the adverse outcomes of gestational hypertension, intrauterine growth restriction (IUGR) and preterm birth and the predictive capacity of the test when applied to this subgroup of high-risk patients. Results Sixty-two women had an elevated serum beta hCG and underwent Doppler study of uterine artery flow velocity waveform. Notching afforded better predictive utility for any outcome than the resistance index alone or in combination with notching. For a composite adverse outcome of any or all of gestational hypertension, birthweight <= 10th centile, and preterm delivery, the presence of a uterine notch alone had sensitivity of 30.7% and specificity of 93.8%. For the identification of severe fetal growth restriction (< 5th centile) and/or preeclampsia, the presence of a notch offered a sensitivity of 50%, specificity of 96.3%, a positive likelihood ratio of 13.5, and a negative likelihood ratio of 0.5. Conclusions The identification of uterine artery notching by means of Doppler ultrasound as a component of the surveillance of women with unexplained elevated beta hCG levels significantly improves the prediction of preeclampsia and/or severe IUGR, although the low prevalence of 13% of these adverse outcomes limits the usefulness of the test in routine clinical practice.