Introduction: 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.
Methods: 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.
Results: 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).
Conclusion: The indices in normal pregnancies were similar to values from previous studies. The values are however not significantly different in pregnancies with abnormal outcome.
Keywords: Uterine artery Doppler; impaired placentation; pulsatility index; resistance index; systolic/diastolic ratio.