Department of Obstetrics and Gynecology, Amsterdam University Medical Center (Location AMC), University of Amsterdam, Amsterdam, The Netherlands.
Unit of Fetal Medicine and Prenatal Diagnosis, Institute for Maternal and Child Health, IRCCS Burlo Garofolo, Trieste, Italy.
Ultrasound Obstet Gynecol. 2021 Nov;58(5):705-715. doi: 10.1002/uog.23615.
First, to compare published Doppler reference charts of the ratios of flow in the fetal middle cerebral and umbilical arteries (i.e. the cerebroplacental ratio (CPR) and umbilicocerebral ratio (UCR)). Second, to assess the association of thresholds of CPR and UCR based on these charts with short-term composite adverse perinatal outcome in a cohort of pregnancies considered to be at risk of late preterm fetal growth restriction.
Studies presenting reference charts for CPR or UCR were searched for in PubMed. Formulae for plotting the median and the 10 percentile (for CPR) or the 90 percentile (for UCR) against gestational age were extracted from the publication or calculated from the published tables. Data from a prospective European multicenter observational cohort study of singleton pregnancies at risk of fetal growth restriction at 32 + 0 to 36 + 6 weeks' gestation, in which fetal arterial Doppler measurements were collected longitudinally, were used to compare the different charts. Specifically, the association of UCR and CPR thresholds (CPR < 10 percentile or UCR ≥ 90 percentile and multiples of the median (MoM) values) with composite adverse perinatal outcome was analyzed. The association was also compared between chart-based thresholds and absolute thresholds. Composite adverse perinatal outcome comprised both abnormal condition at birth and major neonatal morbidity.
Ten studies presenting reference charts for CPR or UCR were retrieved. There were large differences between the charts in the 10 and 90 percentile values of CPR and UCR, respectively, while median values were more similar. In the gestational-age range of 28-36 weeks, there was no relationship between UCR or CPR and gestational age. From the prospective observational study, 856 pregnancies at risk of late-onset preterm fetal growth restriction were included in the analysis. The association of abnormal UCR or CPR with composite adverse perinatal outcome was similar for percentile thresholds or MoM values, as calculated from the charts, and for absolute thresholds, both on univariable analysis and after adjustment for gestational age at measurement, estimated fetal weight MoM and pre-eclampsia. The adjusted odds ratio for composite adverse perinatal outcome was 3.3 (95% CI, 1.7-6.4) for an absolute UCR threshold of ≥ 0.9 or an absolute CPR threshold of < 1.11 (corresponding to ≥ 1.75 MoM), and 1.6 (95% CI, 0.9-2.9) for an absolute UCR threshold of ≥ 0.7 to < 0.9 or an absolute CPR threshold of ≥ 1.11 to < 1.43 (corresponding to ≥ 1.25 to < 1.75 MoM).
In the gestational-age range of 32 to 36 weeks, adjustment of CPR or UCR for gestational age is not necessary when assessing the risk of adverse outcome in pregnancies at risk of fetal growth restriction. The adoption of absolute CPR or UCR thresholds, independent of reference charts, is feasible and makes clinical assessment simpler than if using percentiles or other gestational-age normalized units. The high variability in percentile threshold values among the commonly used UCR and CPR reference charts hinders reliable diagnosis and clinical management of late preterm fetal growth restriction. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.
首先，比较胎儿大脑中动脉和脐动脉血流比值（即脑胎盘比（CPR）和脐脑比（UCR））的已发表多普勒参考图表。其次，评估基于这些图表的 CPR 和 UCR 阈值与被认为有晚期早产胎儿生长受限风险的妊娠队列的短期复合不良围产结局之间的关联。
在 PubMed 中搜索呈现 CPR 或 UCR 参考图表的研究。从中提取或从发表的表格中计算出绘制中位数和第 10 百分位数（CPR）或第 90 百分位数（UCR）与胎龄关系的公式。使用前瞻性欧洲多中心观察性队列研究的数据，该研究纳入了 32+0 至 36+6 周妊娠的胎儿生长受限风险妊娠，在该研究中纵向收集了胎儿动脉多普勒测量值，用于比较不同的图表。具体来说，分析了 UCR 和 CPR 阈值（CPR<10 百分位数或 UCR≥90 百分位数和中位数倍数（MoM）值）与复合不良围产结局的关系。还比较了图表阈值和绝对阈值之间的关联。复合不良围产结局包括出生时的异常情况和主要新生儿发病率。
检索到 10 项呈现 CPR 或 UCR 参考图表的研究。CPR 和 UCR 的第 10 和 90 百分位数值之间存在很大差异，而中位数值则更为相似。在 28-36 周的胎龄范围内，UCR 或 CPR 与胎龄之间没有关系。从前瞻性观察性研究中，纳入了 856 例有晚期早产胎儿生长受限风险的妊娠进行分析。异常 UCR 或 CPR 与复合不良围产结局之间的关联，对于百分位阈值或 MoM 值（根据图表计算）与绝对阈值相似，无论是在单变量分析还是在调整测量时的胎龄、估计胎儿体重 MoM 和子痫前期后。复合不良围产结局的调整比值比为 3.3（95%CI，1.7-6.4），对于绝对 UCR 阈值≥0.9 或绝对 CPR 阈值<1.11（对应于≥1.75 MoM），和 1.6（95%CI，0.9-2.9），对于绝对 UCR 阈值≥0.7 至<0.9 或绝对 CPR 阈值≥1.11 至<1.43（对应于≥1.25 至<1.75 MoM）。
在 32 至 36 周的胎龄范围内，在评估有胎儿生长受限风险的妊娠不良结局风险时，CPR 或 UCR 无需进行胎龄调整。采用独立于参考图表的绝对 CPR 或 UCR 阈值是可行的，比使用百分位数或其他胎龄标准化单位进行临床评估更简单。常用的 UCR 和 CPR 参考图表中百分位阈值值的高度变异性阻碍了晚期早产胎儿生长受限的可靠诊断和临床管理。© 2021 作者。约翰威立父子公司出版由国际超声协会在妇产科超声代表。
