Using Doppler ultrasound to manage the small-for-gestational-age fetus

Abstract

Doppler ultrasound is used to risk assess and monitor high-risk pregnancies to time delivery. Uterine artery (UtA) Doppler is a screening tool for placental dysfunction, as abnormal values represent an increased risk of hypertensive disorders and fetal growth restriction. Routine fetal growth assessment includes measuring the umbilical artery Doppler (UmA), as this reflects placental blood flow and can indicate placental dysfunction. In pregnancies with abnormal UmA Dopplers, assessment of the middle cerebral artery (MCA) and ductus venosus (DV) enables timely delivery by detecting developing hypoxia. In extremely preterm cases of severe growth restriction, the clinical challenge is timing birth so as not to replace the risk of stillbirth with the significant challenges of extreme preterm birth. Here, the DV Doppler is key, as this reflects cardiac function and identifies preterminal acidaemia. The use of each of these Doppler measurements will be described, illustrated and highlighted below using a case summary.