Assessment of Umbilical Artery Doppler Velocities: Which High Risk Conditions Will Benefit the Most?

Doppler Ultrasonography (USS) is a non-invasive imaging modality widely used for antenatal assessment in Obstetrics with an established safety record. Its main use is to determine the flow velocities in the target vessels of a patient. In obstetrics, the technique is commonly utilized to assess the utero-placental and feto-placental transfusion via estimation of blood flow through the uterine and umbilical arteries. Various studies have established the value of umbilical artery Doppler velocities in improving obstetric outcomes via early identification of complications, improved obstetric decision making, minimizing neonatal deaths and avoidance of unnecessary cesarean sections, especially in pregnancies complicated with pre-eclampsia and IUGR. However, likely due to the overhead costs in equipment and training required to allow widespread use of Doppler ultrasonography, only a few studies regarding its use in South Asian populations are available. Further, the unnecessary and excessive use of such tests can contribute to wastage of resources as well as create unnecessary anxiety for pregnant mothers. Therefore, it is pertinent that clear information is available regarding which conditions will benefit most from Doppler studies of the umbilical artery flow velocities. Our study was designed to determine the value of Doppler ultrasonography in several conditions considered as high risk in pregnancy. It is hoped that this study will aid in developing guidelines for optimal use of Doppler ultrasonography in the resource poor setting. Objectives To determine the efficacy of umbilical artery Doppler in managing high risk patients in tertiary care maternal referral center in Colombo, Sri Lanka, a lower-middle income country. Methodology A prospective analytical study was carried out from 1st February 2009 to 31st July 2011 with the inclusion of pregnant mothers presenting to the De Soyza Maternity Hospital (a tertiary care hospital specializing in Obstetrics in Colombo, Sri Lanka) with at least one of - fundus less/more than dates, Amniotic Fluid Index (AFI) 16, Pregnancy Induced Hypertension (PIH), Established Intra-uterine Growth Retardation (IUGR), Chronic medical disorders, Gestational diabetes mellitus or Pre-gestational diabetes mellitus. Those with structural, genetic or chromosomal fetal anomaly, multiple pregnancy, pregnancy complicated with malnutrition or debilitating illness and mothers on oral steroids were excluded from the study. An interviewer administered questionnaire was used for the data collection after the study was explained to each participant and informed written consent obtained. It contained a detailed history and examination as well as most recent blood glucose levels the time of Doppler recording. Comprehensive fetal Doppler measurements were carried out and recorded in accordance with International Society of Ultrasound in Obstetrics and Gynaecology (ISUOG) standards. PI was set at