Preeclampsia and eclampsia are one of major cause of maternal mortality. Various parameters like pulsatility index (PI) and resistivity index (RI) of color Doppler are helpful in detection of preeclampsia and intrauterine growth restriction. The reference ranges of the various parameters like uterine artery PI and RI are mainly from western countries. The reference range for Indian Population is lacking. So the objective of the study is to construct reference range of uterine artery for women from eastern India.
Material and Method
In this study, total 201 pregnant patients were included. Color Doppler of normal pregnant women was done at 18 to 22 weeks and then followed up at 28 to 32 weeks gestation. The uterine artery PI and RI was measured during pregnancy. The obtained data were tabulated and 5th, 25th, 50th, 75th, 90th and 95th percentile was calculated. The reference range was constructed according to gestational age starting from 18 to 22 weeks and then from 28 to 34 weeks. Statistical analysis was performed using SPSS.
The main parameter observed are pulsatility and resistivity index of left and right uterine arteries first at 18 to 22 weeks and then followed up at 28 to 34 weeks. Our data suggests that as the gestational age increases both pulsatility and resistivity index decreases. The cut off value for reference range was taken up to 95th percentile. Anything above 95th percentile is abnormal. The reference range for left uterine artery pulsatility index was found to be 1.19 to 1.16 at 18 to 22 weeks, 1.09 at 28 weeks while 0.89 at 34 weeks. Similarly, the reference range for resistivity index was found to be 0.61 at 18 to 22 weeks while it decreases to 0.54 at 28 to 34 weeks.
Reference range of uterine artery doppler indices for the local population is very useful tool to early prediction of Preeclampsia and IUGRs of that population and can aid in timely treatment of mother and baby. Our data shows decrease in pulsatility and resistivity index with increase in the gestational age.