“Early Screening Test for High Risk Pregnancies by Second Trimester Color Doppler Imaging Of the Feto-Placental Circulation”

Abstract

Objective: To examine the diagnostic value of umbilical artery velocity waveforms for the early detection of pregnancy induced hypertension and fetal growth restriction. To determine the utility of color Doppler Sonography of the fetoplacetal circulation for early detection of high risk pregnancies. Methods: This prospective study was conducted in the Department of Obstetrics & Gynecology, Sir Sallimullah Medical Collage & Mitford Hospital Dhaka in collaboration with radiology and imaging department of Dhaka hospital in 1st July, 2006 to 30 June, 2008. 126 randomly selected patients from 17-35 years of ages whose umbilical artery Doppler sonography was done between 16-22 weeks of gestation. All the patient were taken umbilical artery Doppler ultrasonography. Informed consent was taken from all patients. Results: A total 126 subjects of 16 to 22 weeks of gestation were included in this series. On application of the student‘t’ test for S/D ratio between normal and abnormal waveforms of the umbilical artery was found significant difference (P<.0001). Distribution of patient according to umbilical artery systolic / diastolic ratio (n=126). Normal UA waveform 76 (60%), abnormal UA waveform 50(40%), Age (Mean ±SD) in year, normal UA waveform 25.63 ± 4.47 and abnormal UA waveform 25.86±3.75. Para: Primiparous normal UA waveform 36 (60%) & abnormal UA waveform 24 (40%), multiparous normal UA waveform 40 (60.6%) & abnormal UA waveform 26 (39.4%). Gestation age at scan in weeks (Mean± SD), normal UA waveform 19.5 ±2.5, abnormal UA waveform 19±2.0. Gestation age at delivery in weeks (Mean± SD), normal UA waveform 39.03±1.61, abnormal UA waveform 35.78 ±1.53, P value 0.0001. Birth wt. in Kg. (Mean ±SD), normal UA waveform 3.10 ±0.38, abnormal UA waveform 2.42 ±0.53, P value 0.0001. S/D ratio (Mean ±SD), normal UA waveform 2.40 ±0.31, abnormal UA waveform 5.46±1.62, P value 0.0001. Cases with an abnormal outcome in relation to whether the umbilical artery waveform was classified as normal or abnormal (n=126). Abnormal outcome in PIH normal UA waveform (n=76) 4%, PIH abnormal UA waveform (n=50) 14%, P value 0.001. In PIH/FGR, normal UA waveform (n=76) 1% & abnormal UA waveform (n=50) 5%, P value 0.024. FGR normal UA waveform (n=76) 5% & abnormal UA waveform (n=50) 13%, P value 0.002. Asphyxia normal UA waveform (n=76) 0% & abnormal UA waveform (n=50) 3%, P value 0.017. PIH /IUD normal UA waveform (n=76) 0% & abnormal UA waveform (n=50) 1%. A significant association was found when the Chi Square (X 2) test was used to examine the relationship between umbilical artery blood flow and the outcome of patient (i.e FGR, PIH, fetal asphyxia). The screening test had a sensitivity of 78.26% & specificity of 82.5% and accuracy 80.95%. The predictive value of a positive test was 72% and of a negative test 86.84%. Conclusion : A close linear relationship between diagnosis of high risk pregnancy & umbilical artery Doppler velocity waveforms was observed .As umbilical artery Doppler is easy to perform and it is done in between 16 to 22 weeks of gestation can be done along with anomaly scan which is also done at 20-22 week of gestation. So, UA Doppler does not cause additional USG scan. Along with anomaly scan UA Doppler will help to screen out high risk pregnancy.