Van Leeuwen Peter, Geue Daniel, Lange Silke, Hatzmann Wolfgang, Grönemeyer Dietrich
Department of Biomagnetism, Research and Development Center for Microtherapy (EFMT) Bochum, Germany.
Prenat Diagn. 2003 Nov;23(11):909-16. doi: 10.1002/pd.723.
The aim of this study was to examine changes in the heart rate variability based on the frequency power spectrum of healthy fetuses during the second and third trimester of pregnancy.
We analyzed 222 fetal magnetocardiograms recorded in 49 healthy singleton pregnancies between the 16th and 42nd week. Discrete Fourier transformation was performed on the time-based step function of the RR-intervals. Changes of spectral density in the frequency spectrum in various bands between 0.003 to 1 Hz, including low-frequency (LF: 0.04-0.15 Hz) and high-frequency (HF: 0.15-0.40 Hz) bands, were examined as a function of gestational age.
Spectral density between 0.003 to 1.0 Hz increased with gestational age with large changes, in particular, at lower frequencies. At approximately the 32nd week, the rate of increase in power slowed substantially. Prior to this time, the rates of change in power were different for the bands 0.003 to 0.40 Hz, 0.40 to 0.60 Hz and 0.60 to 1.0 Hz. LF and HF showed similar development, with HF increasing slightly more rapidly.
We conclude that characteristic spectral bands that increase in spectral density at different rates during the second and third trimester may be identified. They most likely reflect developmental changes and behavioral states during pregnancy.
本研究旨在根据妊娠中期和晚期健康胎儿的频率功率谱，研究心率变异性的变化。
我们分析了49例健康单胎妊娠在第16至42周期间记录的222份胎儿心磁图。对RR间期的基于时间的阶跃函数进行离散傅里叶变换。研究了0.003至1Hz不同频段，包括低频（LF：0.04 - 0.15Hz）和高频（HF：0.15 - 0.40Hz）频段的频谱密度随胎龄的变化。
0.003至1.0Hz之间的频谱密度随胎龄增加，变化较大，尤其是在较低频率处。在大约第32周时，功率增加速率大幅放缓。在此之前，0.003至0.40Hz、0.40至0.60Hz和0.60至1.0Hz频段的功率变化速率不同。低频和高频显示出相似的发展趋势，高频增加略快。
我们得出结论，在妊娠中期和晚期可以识别出频谱密度以不同速率增加的特征频段。它们很可能反映了孕期的发育变化和行为状态。
