Fetal internal carotid and umbilical artery blood flow velocity waveforms as a measure of fetal weil-being in intrauterine growth retardation

Abstract

Maximal flow velocity waveforms were re­corded on one occasion from the umbilical artery (UA) and fetal internal carotid artery (ICA) in 240 normal pregnan­cies and 44 cases of intrauterine growth retardation be­tween 26 and 39 wk of gestation. In normal pregnancy the mean UA pulsatility index (PI) decreased from 1.14 (SD: ±0.13) at 26-27 wk of gestation to 0.78 (SD: ±0.15) at 38-39 wk. The corresponding decrease in ICA PI was from 1.63 (SD: ±0.19) to 1.31 (SD: ±0.21). Mean values of UA PI for normal pregnancies were linearly related to gesta­tional age; for ICA PI this relation appeared to be quad­ratic. Normal limits according to age were constructed by estimated means ± 2 SD. In intrauterine growth retarda­tion, the UA PI was increased (>2 SD) in 80% of cases, ICA PI was reduced (>2 SD) in only 45%. The outcome of fetuses with intrauterine growth retardation, as ex­pressed by fetal heart rate abnormality, Apgar score at 1 min, and umbilical cord pH, was significantly related to the UA PI but not to the ICA PI. © 1988 International Pediatrics Research Foundation, Inc.