A study of biorhythm using a power spectral analysis on the fluctuation in fetal and maternal beat-to-beat intervals

对6例正常胎儿、6例妊娠晚期孕妇和7例IUGR胎儿进行了研究。在正常组，同时监测母亲和胎儿，而在IUGR组，仅对胎儿进行逐跳连续监测24小时。对胎儿搏动间期的波动进行功率谱分析。在24小时内，每10分钟计算一个低频区域，即综合低频域(0.025-0.125周期/拍)，6个低频区域的平均值被定义为该小时的低频区域。通过绘制这24个一天的平均LF区域，绘制了一条显示24小时内LF区域波动的曲线。为了检测胎儿一天内波动节律的周期成分，对每小时波动的波动进行了频谱分析。然后，用余弦方法检测低频区域的波动节律。在母亲身上也进行了同样的程序来识别周期性成分。在正常胎儿的自主神经系统活动中发现了12小时周期节律和24小时周期节律。在IUGR胎儿中，由于波幅较小，未观察到这些节律。在母亲身上没有观察到12小时的周期节律，自主神经活动中12小时周期的胎儿节律似乎是特征，这在母亲身上没有观察到。

Six normal fetuses and expectant mothers in the third-trimester pregnancy and seven IUGR fetuses were studied. In the normal group, the mother and the fetus were monitored simultaneously, while in IUGR group only the fetus was monitored continuously for the period of 24 hours on a beat-to-beat basis. A power spectrum analysis was carried out on the fluctuations in fetal beat-to-beat intervals. Over the period of 24 hours, an LF area, integrated low frequency domain (0.025-0.125 cycle/beat), was calculated for every ten minutes, and the average of six LF areas was defined as the LF area for the hour. By plotting these 24 average LF areas obtained for one day, a curve showing the fluctuations in LF areas over the period of 24 hours was drawn. To detect periodic components of a fetal rhythm of the fluctuations in one day, a spectral analysis was carried out on the fluctuations of hourly fluctuation. Then, rhythms of the fluctuations in LF areas were detected by using the cosinor method. In the mother same procedure was performed to identify periodic components.A 12-hour-period rhythm and a 24-hour-period rhythm were found in the activities of the autonomic nervous system of the normal fetuses. In IUGR fetuses, these rhythms were not observed because of the small amplitude. A 12-hour-period rhythm was not observed in the mother.Fetal rhythms of 12 hours cycle in autonomic activity seems to be characteristic, which was not observed in the mother.