Balayla Jacques, Shrem Guy
Department of Obstetrics and Gynecology, McGill University, Montreal, Quebec, Canada.
J Pregnancy. 2020 Feb 8;2020:7801039. doi: 10.1155/2020/7801039. eCollection 2020.
Every year, about 85 percent of the approximately 5 million births in North America are evaluated with the electronic fetal monitoring (EFM). Clinicians use the EFM as a proxy to assess fetal oxygenation status, fetal well-being, and potential compromise. Despite the widespread use of this technology, neonatal hypoxia and acidosis continue to make up a high proportion of neonatal morbidity at term. Indeed, though the fetal heart rhythm is inextricably linked to fetal acid-base status, EFM has not been shown to reliably predict neonatal pH status nor has it reduced adverse maternal or neonatal outcomes. As a consequence, the high false-positive rate of EFM for predicting adverse neonatal outcomes has led to an increase in the rate of operative vaginal and cesarean delivery, with elevated rates of associated maternal and neonatal morbidity. This fact invariably leads to a paradox we have henceforth defined as the "obstetrical paradox." Herein, we explore the potential solutions to this paradox and introduce a novel noninvasive technique to assess fetal acid-base status in utero known as the "FETAL technique" (Fourier Evaluation of Tracings and Acidosis in Labour). The FETAL technique, currently under investigation, applies the discrete Fourier transformation to EFM tracings to determine the spectral frequency distribution of the fetal heart rate. These specific frequency distributions correlate with specific umbilical pH values and may provide the missing link between fetal heat rate patterns and acid-base status at birth. As we work toward realizing the full potential benefits of EFM, finding the best assessment strategies to evaluate fetal pH in real time remains a key goal in obstetrics.
在北美，每年约500万例分娩中，约85%会接受电子胎儿监护（EFM）评估。临床医生使用EFM作为评估胎儿氧合状态、胎儿健康状况及潜在风险的替代方法。尽管这项技术被广泛应用，但新生儿缺氧和酸中毒在足月新生儿发病率中仍占很高比例。事实上，虽然胎儿心律与胎儿酸碱状态密切相关，但EFM尚未被证明能可靠预测新生儿的pH值状态，也未降低孕产妇或新生儿的不良结局。因此，EFM预测新生儿不良结局的高假阳性率导致了阴道助产和剖宫产率的上升，以及相关孕产妇和新生儿发病率的增加。这一事实不可避免地导致了一个我们此后定义为“产科悖论”的矛盾。在此，我们探讨这一悖论的潜在解决方案，并介绍一种新的评估子宫内胎儿酸碱状态的非侵入性技术，即“FETAL技术”（产时胎心率曲线傅里叶评估与酸中毒）。目前正在研究的FETAL技术，将离散傅里叶变换应用于EFM曲线，以确定胎儿心率的频谱频率分布。这些特定的频率分布与特定的脐动脉pH值相关，可能提供胎儿心率模式与出生时酸碱状态之间缺失的联系。在我们努力实现EFM的全部潜在益处的过程中，找到实时评估胎儿pH值的最佳策略仍然是产科的一个关键目标。
