1993 Fiscal Year Final Research Report Summary
Research of fetal circulation dynamics by means of cross-correlation of the fetal heart rates between twin fetuses
| Project/Area Number |
04454413
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Obstetrics and gynecology
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| Research Institution | University of Tsukuba |
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Principal Investigator |
KUBO Takeshi University of Tsukuba Inst.of clinical medicine Professor, 臨床医学系, 教授 (20010267)
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| Co-Investigator(Kenkyū-buntansha) |
SHIGEMITSU Sadahiko University of Tsukuba Inst.of clinical medicine Assistant Professor, 臨床医学系, 講師 (20235526)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Twin / Fetal heart rate / Cross-correlation / Dynamics of fetal circulation |
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| Research Abstract |
When non-stress test (NST) is performed for twins by a simultaneous fetal heart rate monitor, we often observe a similar pattern in the traces of CTGs of both fetuses during same time interval. We investigated this similarity of the heart rates patterns by means of a crosscorrelation function.
In our university hospital, the NST was performed for twin fetuses with a cardiotocomonitor for twins (TOITU, MT-430), and the output fetal heart rate from the monitor was collected to a personal computer through an A/D converter. Sampling time of the converter was 0.2 sec. and the NST was performed for about 25 minutes. Crosscorrelation function was calculated from the data of the fetal heart rates, and a maximum value of the crosscorrelation coefficient was measured as a peak value and a delay time.
We analyzed 55 traces of 13 cases of which gestational age were from 25 to 38 weeks. In an active phase we were able to find a peak of crosscorrelation function calculated from the CTG.Value of the peak was greater than 0.20 in the most traces, and its mean and S.D.were 0.433 and 0.164 respectively. The average delay time of the peak was 12.4 seconds. In a resting phase most traces have no typical peak of the crosscorrelation function and mean and S.D.of the peak value were 0.191 and 0.215. There were no obvious relationship between the crosscorrelation and gestational age, and no characteristic difference between the crosscorrelation functions of mono-chorionic and di-chorionic twins.
It was suggested that the similarity of the fetal heart rate trace between twin fetuses was derived chiefly from the acceleration in the active phase. The average time difference of the acceleration in both fetuses was about 12 seconds, and it was suggestive of difference in the heart rate response to the tactile stimulation.
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