Dalton K J, Denman D W, Dawson A J, Hoffman H J
Int J Biomed Comput. 1986 Jan;18(1):45-60. doi: 10.1016/0020-7101(86)90045-0.
Even though fetal heart rate recordings are widely used to monitor fetal health, both antenatally and in labour, the underlying physiology is not well understood. For example, it is not known with any certainty whether the oscillations seen in fetal heart rate are highly organised, in reflection of underlying ultradian rhythms, or whether they are entirely random and haphazard. In order to answer this question, therefore, we have used mathematical techniques of time series analysis to look for clear evidence of ultradian rhythms in fetal heart rate recordings. We have found that specific short-term ultradian rhythms are indeed present, and that they can be measured objectively in terms of their frequency, amplitude and phase. Such rhythms have cycle lengths of 10 to 90 s and they can persist for long periods of time. They may also disappear and later reappear, locking back into synchrony again with previous oscillations. Individual rhythms may undergo amplitude change, phase shift, and perhaps even frequency shift.
尽管胎儿心率记录被广泛用于产前和分娩期间监测胎儿健康，但其中潜在的生理学机制尚未得到充分理解。例如，目前尚不能确定胎儿心率中观察到的波动是高度有组织的，反映了潜在的超日节律，还是完全随机且杂乱无章的。因此，为了回答这个问题，我们运用了时间序列分析的数学技术，在胎儿心率记录中寻找超日节律的明确证据。我们发现特定的短期超日节律确实存在，并且可以根据其频率、振幅和相位进行客观测量。这些节律的周期长度为10至90秒，并且可以长时间持续。它们也可能消失，随后再次出现，并再次与先前的波动锁定同步。个别节律可能会发生振幅变化、相位偏移，甚至可能发生频率偏移。
