Umbilical arterial Doppler ultrasonography predicts late pregnancy outcomes in patients with lupus nephritis: a multicenter study from southern China

Objectives: To investigate the fetal adverse pregnancy outcomes (APOs) and the predictive value of umbilical arterial Doppler ultrasonography in the third trimester in pregnant women with lupus nephritis (LN). Methods: A retrospective cohort study enrolling 203 LN patients from 2007 to 2017 was performed. Ultrasonic parameters were recorded. Results: Fetal APOs occurred in 103 patients (103/203, 50.7%). Sixty-six pregnancies (66/203, 32.5%) ended with preterm births. The incidence rate of intrauterine growth restriction (IUGR) was 18.2% (37/203). Fetal distress was noted in 23 pregnancies (23/203, 11.3%). All the Doppler parameters elevated in patients with IUGR, fetal distress, and composite conditions. Resistance index (RI) indicated the highest risk of IUGR and composite APOs. The cutoff values were 0.66 and 0.67, respectively. Sensitivities were 51.4% and 33.7%, and specificities were 87.4% and 92.1%. Peak velocity of the umbilical arteries at end-systole (Vmax, abbreviated as S) to that at end-diastole (Vmin, abbreviated as D) (S/D) ratio was also a best predictor for IUGR, with the optimal cutoff value of 2.88. Sensitivity and specificity were comparable with RI. Pulsatility index (PI) over 0.84 was an ideal indicator for fetal distress with an optimal combination of sensitivity (89.5%) and specificity (51.6%). Conclusions: Fetal complications were frequent in patients with LN. Umbilical arterial Doppler ultrasonography was a useful measure to predict late IUGR, fetal distress, and the composite APOs.