Objectives

Fetal arterial Doppler measurements are associated with the quality of neonatal GMs 1 week after birth, but this association is no longer evident at 3 months post-term. Brain sparing in particular is associated strongly with GMs of an abnormal quality. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Objectives:In intrauterine growth restriction (IUGR), one method to monitor fetal condition is to measure flow velocity of the fetal vessels. By calculating the pulsatility index (PI) of the umbilical artery (UA), the middle cerebral artery (MCA), and calculating the cerebroplacental ratio (CPR i.e. MCA/UA), fetal blood flow redistribution (brain sparing) can be quantified. It is unknown whether the degree of alterations of the fetal flow profiles persist during the first days after birth. Our objective was to assess whether fetal brain sparing persists after birth. Methods: Consecutive IUGR fetuses presenting at the Department of Obstetrics were included. IUGR diagnosis was based on abdominal circumference < P10 or deflecting fetal growth. Fetal Doppler parameters were measured serially and the last measurement was taken maximum 1 week prior to delivery. Decision to deliver was based on local protocols not including Doppler parameters. After birth, we used near-infrared spectroscopy (NIRS) to measure regional tissue oxygen saturation (rSO2) of cerebral and renal tissue for 2 hours per day from day 1 to 5. Additionally we measured transcutaneous oxygen saturation (SpO2). Fractional tissue oxygen extraction was calculated for each region as FTOE = (SpO2-rS02)/SpO2. Outcome measures were cerebral and renal FTOE and cerebrorenal ratio (CRR i.e. cerebral/renal FTOE). Results: Of 42 IUGR infants 52% was admitted to the NICU, 45% was male. Median birthweight was 1808 grams and median gestational age 36.9 weeks. Correlation coefficients of day 1 to 3 are shown in table 1. On day 4 and 5 correlations between cerebral FTOE and PI measures were not significant, whereas renal FTOE and CRR correlated significantly with all PI measures (p < 0.05). Conclusions: High PI of the UA indicates diminished fetal wellbeing, low PI of the MCA and low CPR both indicate fetal brain sparing. These parameters are strongly associated with a low CRR, indicating a relatively higher oxygen delivery, thus higher blood supply to the cerebrum than to the renal region. We speculate that if brain sparing is present in fetal circulation, it persists for the first 5 days after birth.