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COMPUTER ANALYSIS OF FETAL HEART RATE VARIATION DURING NORMAL PREGNANCY
Author(s) -
Wheeler T.,
Cooke E.,
Murrills A.
Publication year - 1979
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/j.1471-0528.1979.tb10592.x
Subject(s) - gestation , standard deviation , fetus , coefficient of variation , medicine , cardiology , heart rate , pregnancy , mathematics , statistics , biology , blood pressure , genetics
Summary Ninety‐seven one‐hour recordings of the abdominal fetal electrocardiogram (ECG) were made from 59 normal patients between 21 and 41 weeks of gestation. The heart intervals, measured between successive R‐waves, were analysed by computer. The signal‐to‐noise ratio of the fetal ECG limited the precision of the interval measurements to approximately one millisecond. The characteristics of the baseline heart rate changed significantly as gestation advanced, the mean R‐R interval, the standard deviation of the intervals and the standard deviation of the interval differences all increasing with gestation (p <0.001). In later gestation the baseline heart rate during periods of fetal rest differed significantly from that during periods of fetal activity; during rest the mean R‐R interval was greater (p <0.001) and the standard deviations of the intervals and interval differences were smaller (p <0.001). Examination of the coefficient of variation of the heart intervals gave a result which contradicted the significance of this measurement as an index of fetal welfare as proposed by Curran and MacGregor (1970).