Zizzo Anne Rahbek, Kirkegaard Ida, Hansen John, Uldbjerg Niels, Mølgaard Henning
Department of Obstetrics and Gynecology, Aarhus University Hospital, Aarhus, Denmark.
Department of Health Science and Technology, Aalborg University, Aalborg, Denmark.
Front Physiol. 2020 Sep 30;11:578898. doi: 10.3389/fphys.2020.578898. eCollection 2020.
Fetal heart rate variability (FHRV) evaluates the fetal neurological state, which is poorly assessed by conventional prenatal surveillance including cardiotocography (CTG). Accurate FHRV on a beat-to-beat basis, assessed by time domain and spectral domain analyses, has shown promising results in the scope of fetal surveillance. However, accepted standards for these techniques are lacking, and the influence of fetal breathing movements and gross movements may be especially challenging. Thus, current standards for equivalent assessments in adults prescribe rest and controlled respiration. The aim of this review is to clarify the importance of fetal movements on FHRV. A systematic review in accordance with the PRISMA guidelines based on publications in the EMBASE, the MEDLINE, and the Cochrane Library databases was performed. Studies describing the impact of fetal movements on time domain, spectral domain and entropy analyses in healthy human fetuses were reviewed. Only studies based on fetal electrocardiography or fetal magnetocardiography were included. PROSPERO registration number: CRD42018068806. In total, 14 observational studies were included. Fetal movement detection, signal processing, length, and selection of appropriate time series varied across studies. Despite these divergences, all studies showed an increase in overall FHRV in the moving fetus compared to the resting fetus. Especially short-term, vagal mediated indexes showed an increase during fetal breathing movements including an increase in Root Mean Square of the Successive Differences (RMSSD) and High Frequency power (HF) and a decrease in Low Frequency power/High Frequency power (LF/HF). These findings were present even in analyses restricted to one specific fetal behavioral state defined by Nijhuis. On the other hand, fetal body movements seemed to increase parameters supposed to represent the sympathetic response [LF and Standard Deviation of RR-intervals from normal sinus beats (SDNN)] proportionally more than parameters representing the parasympathetic response (RMSSD, HF). Results regarding entropy analyses were inconclusive. Time domain analyses as well as spectral domain analyses are affected by fetal movements. Fetal movements and especially breathing movements should be considered in these analyses of FHRV.
胎儿心率变异性（FHRV）用于评估胎儿的神经状态，而传统的产前监测方法（包括胎心监护（CTG））对其评估效果不佳。通过时域和频域分析逐搏评估的准确FHRV在胎儿监测领域已显示出有前景的结果。然而，这些技术缺乏公认的标准，胎儿呼吸运动和大运动的影响可能尤其具有挑战性。因此，目前成人等效评估的标准规定要休息并控制呼吸。本综述的目的是阐明胎儿运动对FHRV的重要性。我们根据PRISMA指南，对EMBASE、MEDLINE和Cochrane图书馆数据库中的出版物进行了系统综述。回顾了描述胎儿运动对健康人类胎儿时域、频域和熵分析影响的研究。仅纳入基于胎儿心电图或胎儿磁心动图的研究。PROSPERO注册号：CRD42018068806。总共纳入了14项观察性研究。不同研究之间，胎儿运动检测、信号处理、时长以及合适时间序列的选择各不相同。尽管存在这些差异，但所有研究均表明，与静止胎儿相比，运动胎儿的总体FHRV有所增加。特别是短期而言，迷走神经介导的指标在胎儿呼吸运动期间有所增加，包括逐次差分均方根（RMSSD）和高频功率（HF）增加，低频功率/高频功率（LF/HF）降低。即使在仅限于由尼胡伊斯定义的一种特定胎儿行为状态的分析中，这些发现依然存在。另一方面，胎儿身体运动似乎使代表交感神经反应的参数[LF和正常窦性心律RR间期标准差（SDNN）]比代表副交感神经反应的参数（RMSSD、HF）增加得更多。关于熵分析的结果尚无定论。时域分析以及频域分析均受胎儿运动影响。在这些FHRV分析中应考虑胎儿运动，尤其是呼吸运动。
