Uterine artery Doppler study in second trimester of pregnancy

The uterine artery Doppler has potentials for screening for complications of impaired placentation. This study examines the indices of uterine artery impedance at 22-23 weeks gestation and their relationship with maternal age and parity.

Uterine artery colour imaging and pulsed wave Doppler ultrasound was conducted between 22nd and 23rd weeks in 430 pregnancies. The pregnancies were classified into 2 groups: normal and abnormal outcomes. The indices of impedance recorded were pulsatility index, resistance index and the systolic/diastolic ratio. Relevant obstetric information was retrieved from the antenatal records. The student t- test and Pearson's product moment were used for statistical analysis.

Fifty eight (13.5%) out of 430 pregnancies had complications of impaired placentation, mainly intrauterine growth restriction and preterm birth (24 or 41.4% each). The indices in normal pregnancies were similar to presently used values. There was no statistically significant difference in the 2 pregnancies groups. The Pulsatility Index (PI) in the right uterine artery was statistically different from the left (t-test 32.8, p < 0.05). Maternal age and parity demonstrate statistically significant positive correlation with PI (r =0.9, p < 0.05; r =0.8, p < 0.05).

The indices in normal pregnancies were similar to values from previous studies. The values are however not significantly different in pregnancies with abnormal outcome.