Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
Institute of Health Research, University of Exeter, Exeter, UK.
Ultrasound Obstet Gynecol. 2019 Apr;53(4):465-472. doi: 10.1002/uog.20157. Epub 2019 Feb 13.
To develop gestational age-based reference ranges for the pulsatility index in the umbilical artery (UA-PI) and fetal middle cerebral artery (MCA-PI) and the cerebroplacental ratio (MCA-PI/UA-PI), and to examine the maternal characteristics and medical history that affect these measurements.
This was a cross-sectional study of 72 387 pregnancies undergoing routine ultrasound examination at 20 + 0 to 22 + 6 weeks' gestation (n = 3712), 31 + 0 to 33 + 6 weeks (n = 29 035), 35 + 0 to 36 + 6 weeks (n = 37 252) or 41 + 0 to 41 + 6 weeks (n = 2388). For the purpose of this study, we included data for only one of the second- or third-trimester visits. The inclusion criteria were singleton pregnancy, dating by fetal crown-rump length at 11 + 0 to 13 + 6 weeks' gestation, live birth of a morphologically normal neonate and ultrasonographic measurements by sonographers who had received the Fetal Medicine Foundation Certificate of Competence in Doppler ultrasound. Since the objectives of the study were to establish reference ranges, rather than normal ranges, and to examine factors from maternal characteristics and medical history that affect these measurements, we included all pregnancies having routine ultrasound examinations, irrespective of whether the mother had a pre-existing medical condition, such as diabetes mellitus, or a pregnancy complication, such as pre-eclampsia or suspected fetal growth restriction. Median and SD models were fitted between UA-PI, MCA-PI and CPR and gestational age. Assessment of goodness of fit of the models was by inspection of quantile-to-quantile (Q-Q) plots of Z-scores calculated using the mean and SD models. The distributions of MCA-PI, UA-PI and CPR Z-scores were examined in relation to maternal characteristics and medical history.
The relationship between the median and gestational age was linear for UA-PI and cubic for MCA-PI and CPR and the SD was log quadratic for all three. MCA-PI and CPR increased with gestational age from 20 weeks' gestation to reach a peak at around 32 and 34 weeks, respectively, and decreased thereafter, whereas UA-PI decreased linearly with gestational age from 20 to 42 weeks. Compared to the general population, significant deviations in multiples of the median values of UA-PI, MCA-PI and CPR were observed in subgroups of maternal age, body mass index, racial origin, method of conception and parity.
This study established new reference ranges for UA-PI, MCA-PI and CPR, according to gestational age, and reports maternal characteristics and medical history that affect these measurements. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.
制定基于胎龄的脐动脉（UA-PI）和胎儿大脑中动脉（MCA-PI）搏动指数以及脑胎盘比（MCA-PI/UA-PI）的参考范围，并探讨影响这些测量值的母体特征和病史。
这是一项横断面研究，纳入了 72387 例孕 20+0 至 22+6 周（n=3712）、31+0 至 33+6 周（n=29035）、35+0 至 36+6 周（n=37252）或 41+0 至 41+6 周（n=2388）妊娠妇女的常规超声检查数据。出于本研究的目的，我们仅纳入了其中一次孕晚期检查的数据。纳入标准为单胎妊娠、孕 11+0 至 13+6 周时胎儿头臀长估计的孕龄、形态正常新生儿的活产儿和接受过胎儿医学基金会多普勒超声能力证书认证的超声医师进行的超声测量。由于本研究的目的是建立参考范围，而不是正常范围，并探讨影响这些测量值的母体特征和病史因素，因此我们纳入了所有进行常规超声检查的妊娠妇女，无论其母亲是否存在糖尿病等预先存在的医疗状况或子痫前期或疑似胎儿生长受限等妊娠并发症。在 UA-PI、MCA-PI 和 CPR 与胎龄之间拟合中位数和标准差模型。通过检查使用均值和标准差模型计算的 Z 分数的分位数-分位数（Q-Q）图来评估模型拟合优度。检查了 MCA-PI、UA-PI 和 CPR Z 分数分布与母体特征和病史的关系。
UA-PI 的中位数与胎龄呈线性关系，MCA-PI 和 CPR 的中位数与胎龄呈立方关系，而所有三个的标准差均呈对数二次关系。MCA-PI 和 CPR 从 20 孕周开始随胎龄增加，分别在约 32 周和 34 周达到峰值，此后逐渐下降，而 UA-PI 则从 20 周至 42 周随胎龄线性下降。与一般人群相比，UA-PI、MCA-PI 和 CPR 的中位数倍数的显著偏差出现在母体年龄、体重指数、种族起源、受孕方式和产次的亚组中。
本研究根据胎龄制定了新的 UA-PI、MCA-PI 和 CPR 参考范围，并报告了影响这些测量值的母体特征和病史。版权所有©2018 ISUOG。由 John Wiley & Sons Ltd 出版。
