Antenatal Doppler screening for fetuses at risk of adverse outcomes: a multicountry cohort study of the prevalence of abnormal resistance index in low-risk pregnant women

INTRODUCTION: Few interventions exist to address the high burden of stillbirths in apparently healthy pregnant women in low- and middle-income countries (LMICs). To establish whether a trial on the impact of routine Doppler screening in a low-risk obstetric population is warranted, we determined the prevalence of abnormal fetal umbilical artery resistance indices among low-risk pregnant women using a low-cost Doppler device in five LMICs. METHODS: We conducted a multicentre, prospective cohort study in Ghana, India, Kenya, Rwanda and South Africa. Trained nurses or midwives performed a single, continuous-wave Doppler screening using the Umbiflow device for low-risk pregnant women (according to local guidelines) between 28 and 34 weeks' gestation. We assessed the prevalence of abnormal (raised) resistance index (RI), including absent end diastolic flow (AEDF), and compared pregnancy and health service utilisation outcomes between women with abnormal RI versus those with normal RI. RESULTS: Of 7151 women screened, 495 (6.9%) had an abnormal RI, including 14 (0.2%) with AEDF. Caesarean section (40.8% vs 28.1%), labour induction (20.5% vs 9.0%) and low birth weight (<2500 g) (15.0% vs 6.8%) were significantly more frequent among women with abnormal RI compared with women with normal RI. Abnormal RI was associated with lower birth weights across all weight centiles. Stillbirth and perinatal mortality rates were similar between women with normal and abnormal RI. CONCLUSION: A single Doppler screening of low-risk pregnant women in LMICs using the Umbiflow device can detect a large number of fetuses at risk of growth restriction and consequent adverse perinatal outcomes. Many perinatal deaths could potentially be averted with appropriate intervention strategies. TRIAL REGISTRATION NUMBER: CTRI/2018/07/01486.