Comparative study of transabdominal and transvaginal uterine artery Doppler pulsatility indices at 11-13 + 6 weeks

The objective of this study was to compare two approaches to determine the uterine artery pulsatility index (PI) as a screening measure for preeclampsia.

Comparative analysis of the PI values obtained from transabdominal and transvaginal Doppler ultrasound in 351 women with singleton pregnancies who were examined between May and June 2009 during routine morphological study and risk calculation of chromosome anomalies at 11-13 + 6 weeks of gestation.

The mean PI measured transabdominally was 1.83 [95% confidence interval (CI) 1.78-1.89], but when measured transvaginally it was 1.98 (95% CI 1.93-2.08) (p < 0.05). Transabdominal mean PI was observed to decrease as the crown-rump length (CRL) increased: 1.96 (95% CI 1.80-2.12) for CRL <60 mm and 1.71 (95% CI 1.56-1.87) for CRL ≥70 mm (p < 0.05). The transvaginally measured indices were 2.09 (95% CI 1.93-2.26) and 1.78 (95% CI 1.64-1.92), respectively, for the same CRL groups (p < 0.05). A weak correlation was found between the mean PI and the mean CRL using Spearman's rho correlation (-0.20 for abdominal measures and -0.21 for vaginal measures, p < 0.001).

Transabdominal and transvaginal Doppler ultrasound measurements of the uterine artery PI were significantly different. The latter approach yielded significantly higher values than the first.