Longitudinal Doppler Assessments in Late Preterm Fetal Growth Restriction.

Purpose To assess the longitudinal variation of the ratio of umbilical and cerebral artery pulsatility index (UCR) in late preterm fetal growth restriction (FGR). Materials and Methods A prospective European multicenter observational study included women with a singleton pregnancy, 32+ 0–36+ 6, at risk of FGR (estimated fetal weight [EFW] or abdominal circumference [AC]  40 percentile points). The primary outcome was a composite of abnormal condition at birth or major neonatal morbidity. UCR was categorized as normal ( Results 856 women had 2770 measurements; 696 (81 %) had more than one measurement (median 3 (IQR 2–4). At inclusion, 63 (7 %) a UCR ≥ 0.9. These delivered earlier and had a lower birth weight and higher incidence of adverse outcome (30 % vs. 9 %, relative risk 3.2; 95 %CI 2.1–5.0) than women with a normal UCR at inclusion. Repeated measurements after an abnormal UCR at inclusion were abnormal again in 67 % (95 %CI 55–80), but after a normal UCR the chance of finding an abnormal UCR was 6 % (95 %CI 5–7 %). The risk of composite adverse outcome was similar using the first or subsequent UCR values. Conclusion An abnormal UCR is likely to be abnormal again at a later measurement, while after a normal UCR the chance of an abnormal UCR is 5–7 % when repeated weekly. Repeated measurements do not predict outcome better than the first measurement, most likely due to the most compromised fetuses being delivered after an abnormal UCR.