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. 2021 Jul;58(1):67-76. doi: 10.1002/uog.23623. Epub 2021 Jun 9.
There were two objectives of this study. First, to examine the value of uterine artery pulsatility index (UtA-PI) at 19-24 weeks' gestation in the prediction of subsequent development of pre-eclampsia (PE) and to compare the performance of screening between the use of, first, fixed cut-offs of UtA-PI, second, percentile cut-offs of UtA-PI adjusted for gestational age, third, a competing-risks model combining maternal demographic characteristics and medical history with UtA-PI, and, fourth, a competing-risks model combining maternal factors with UtA-PI and mean arterial pressure (MAP). Second, to stratify pregnancy care based on the estimated risk of PE at 19-24 weeks' gestation from UtA-PI and combinations of maternal factors with UtA-PI and MAP.
This was a prospective, non-intervention study in women attending for an ultrasound scan at 19-24 weeks as part of routine pregnancy care. Patient-specific risks of delivery with PE at < 36 weeks' gestation were calculated using the competing-risks model to combine the prior distribution of the gestational age at delivery with PE, obtained from maternal characteristics and medical history, with multiples of the median (MoM) values of UtA-PI and MAP. Different risk cut-offs were used to vary the proportion of the population stratified into each risk category (very high risk, high risk, intermediate risk and low risk) with the intention of detecting about 80%, 85%, 90% and 95% of cases of delivery with PE at < 28, < 32 and < 36 weeks' gestation. We also examined the performance of screening by maternal factors and UtA-PI MoM, fixed cut-offs of UtA-PI and percentile cut-offs of UtA-PI adjusted for gestational age. Calibration for risks for PE < 36 weeks' gestation by the combination of maternal factors, UtA-PI MoM and MAP MoM was assessed by plotting the observed incidence of PE against the predicted incidence. Additionally, we developed reference ranges of transabdominal and transvaginal measurement of UtA-PI according to gestational age.
In the study population of 96 678 singleton pregnancies, there were 2866 (3.0%) that subsequently developed PE, including 467 (0.5%) that delivered at < 36 weeks' gestation. If the objective of screening was to identify about 90% of cases of delivery with PE at < 28, < 32 and < 36 weeks and the method of screening was a combination of maternal factors, UtA-PI MoM and MAP MoM, the proportion of the population stratified into very high-risk, high-risk, intermediate-risk and low-risk groups would be 2.4%, 3.9%, 17.8% and 75.9%, respectively; the respective values were 6.0%, 3.0%, 21.0% and 70.0% if screening was by maternal factors and UtA-PI MoM, 5.7%, 7.5%, 49.8% and 37.0% if screening was by fixed cut-offs of UtA-PI and 6.9%, 5.2%, 49.0% and 38.9% if screening was by percentile cut-offs of UtA-PI. In the validation of the prediction model based on a combination of maternal factors and MoM values of UtA-PI and MAP, calibration plots demonstrated good agreement between the predicted risk and the observed incidence of PE.
All pregnant women should have screening for PE at 20 and 36 weeks' gestation. The findings at 20 weeks can be used to identify the subgroups that require additional monitoring and reassessment at 28 and 32 weeks. The performance of screening by a combination of maternal factors and MoM values of UtA-PI and MAP at 19-24 weeks for delivery with PE at < 28, < 32 and < 36 weeks' gestation is superior to that of screening by a combination of maternal factors and UtA-PI MoM, by fixed cut-offs of UtA-PI or by percentile cut-offs of UtA-PI. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.
本研究有两个目的。第一，检验妊娠 19-24 周时子宫动脉搏动指数（UtA-PI）在预测随后发生子痫前期（PE）中的价值，并比较使用固定 UtA-PI 截断值、妊娠年龄校正的 UtA-PI 百分位截断值、结合母体人口统计学特征和病史的竞争风险模型、以及结合 UtA-PI 和平均动脉压（MAP）的竞争风险模型进行筛查的效能。第二，根据妊娠 19-24 周时 UtA-PI 及 UtA-PI 和 MAP 与母体因素的组合估计的 PE 发病风险，对妊娠进行分层。
这是一项前瞻性、非干预性研究，在常规妊娠护理中，对 19-24 周进行超声检查的妇女进行研究。使用竞争风险模型计算在 <36 周分娩时发生 PE 的患者特异性风险，该模型将 PE 时分娩的平均孕龄与来自母体特征和病史的先验分布相结合，与 UtA-PI 和 MAP 的中位数倍数（MoM）值相乘。使用不同的风险截断值来改变每个风险类别的人群分层比例（极高风险、高风险、中风险和低风险），目的是检测约 80%、85%、90%和 95%的<28 周、<32 周和<36 周分娩的 PE 病例。我们还检查了通过母体因素和 UtA-PI MoM、固定 UtA-PI 截断值和妊娠年龄校正的 UtA-PI 百分位截断值进行筛查的效能。通过绘制观察到的 PE 发生率与预测的 PE 发生率来评估结合母体因素、UtA-PI MoM 和 MAP MoM 的 PE<36 周的风险校准。此外，我们根据妊娠年龄制定了经腹和经阴道测量 UtA-PI 的参考范围。
在 96678 例单胎妊娠的研究人群中，有 2866 例（3.0%）随后发生了 PE，其中 467 例（0.5%）在<36 周分娩。如果筛查的目的是检测约 90%的<28 周、<32 周和<36 周分娩的 PE 病例，并且筛查方法是结合母体因素、UtA-PI MoM 和 MAP MoM，那么将人群分层为极高风险、高风险、中风险和低风险组的比例分别为 2.4%、3.9%、17.8%和 75.9%；如果筛查方法是母体因素和 UtA-PI MoM，则分别为 6.0%、3.0%、21.0%和 70.0%；如果筛查方法是固定的 UtA-PI 截断值，则分别为 5.7%、7.5%、49.8%和 37.0%；如果筛查方法是百分位 UtA-PI 截断值，则分别为 6.9%、5.2%、49.0%和 38.9%。在基于母体因素和 UtA-PI 和 MAP MoM 值的预测模型验证中，校准图表明预测风险与 PE 的观察发生率之间具有良好的一致性。
所有孕妇都应在 20 和 36 周时进行 PE 筛查。20 周时的发现可用于识别需要在 28 周和 32 周时进行额外监测和重新评估的亚组。妊娠 19-24 周时，与母体因素和 UtA-PI MoM 的结合相比，与 UtA-PI 和 MAP 的结合筛查在<28 周、<32 周和<36 周时发生 PE 的效能更高。<28 周、<32 周和<36 周时，固定 UtA-PI 截断值或 UtA-PI 百分位截断值的筛查效能优于结合母体因素和 UtA-PI MoM 的筛查效能。© 2021 年国际妇产科超声学会。
