Diagnostic evaluation of uterine artery Doppler sonography for the prediction of adverse pregnancy outcomes

BACKGROUND: Increased impedance to flow in the uterine arteries assessed by value of the Doppler is associated with adverse pregnancy outcomes, especially pre-eclampsia. We investigated the predictive value of a uterine artery Doppler in the identification of adverse pregnancy outcomes such as ‘pre-eclampsia’ and ‘small fetus for gestational age’ (SGA). MATERIALS AND METHODS: Three hundred and seventy-nine women, with singleton pregnancy, between 18 and 40 years of age, without risk factors, randomly underwent Doppler interrogation of the uterine arteries, between 16-22 weeks of gestation. Those who had a mean pulsatility index (PI) of >1.45 were considered to have an abnormal result, and were evaluated and compared with those who had normal results for adverse pregnancy outcomes, including pre-eclampsia and small for gestational age. The relationship between the variables was assessed with the use of the chi-square test. RESULTS: There were 17 cases (4.5%) of abnormal uterine artery Doppler results and 15 of them (88.2%) developed pre-eclampsia and four cases (23.5%) had neonates small for gestational age. For predicting pre-eclampsia, the mean uterine artery PI had to be >1.45, had to have a specificity of 95.5% (95% CI, 70-92%), a sensitivity of 79% (95% CI, 43-82%), a negative predictive value (NPV) of 98.9% (95% CI, 72-96%), and a positive predictive value (PPV) of 88.2% (95% CI, 68-98%). In the case of ‘small for gestational age’ it had to have a specificity of 96.5% (95% CI, 42-68%), a sensitivity of 57% (95% CI, 53-76%), an NPV of 99.2% (95% CI, 70-92%), and a PPV of 23.5% (95% CI, 30-72%). CONCLUSION: Uterine artery Doppler evaluation at 16-22 weeks of gestation might be an appropriate tool for identifying pregnancies that may be at an increased risk for development of pre-eclampsia and small fetus for gestational age.