The application of uterine and umbilical artery velocimetry to the antenatal supervision of pregnancies complicated by maternal sickle hemoglobinopathies

Abstract

To assess the efficacy of Doppler flow velocimetry in predicting fetal compromise and neonatal outcome in pregnant women with sickle cell hemoglobinopathies, a prospective study was conducted of 96 patients, 48 with sickle cell hemoglobinopathy (8 with SS and 40 with AS hemoglobin) and 48 low-risk AA hemoglobin controls. All subjects were followed biweekly from the third trimester of pregnancy through delivery with uterine and umbilical artery velocimetry, nonstress, tests, and hematocrit and blood pressure measurements. An abnormal systolic/diastolic ratio was defined as a value greater than or equal to 3. The incidence of abnormal systolic/diastolic ratios for uterine or umbilical arteries was significantly higher in pregnant women with SS hemoglobin (88%) when compared with patients with AS (7%) and AA (4%) hemoglobin. In addition, the abnormal systolic/diastolic ratios for both umbilical and uterine arteries are correlated with abnormal nonstress test results. The nonstress test results became abnormal on average 3 weeks after the systolic/diastolic ratios did. The presence of abnormal systolic/diastolic ratios for umbilical and uterine arteries is predictive of fetal distress and infants small for gestational age. The high incidence of concordant uterine and umbilical artery abnormal systolic/diastolic ratios in pregnant women with SS hemoglobinopathy, which were identified earlier than were abnormal nonstress results, suggests an important parameter in the monitoring of these high-risk pregnancies.