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Erschienen in:
01.03.2010 | Original Article
Sleep–wake cycles in normal fetuses
Erschienen in: Archives of Gynecology and Obstetrics | Ausgabe 3/2010
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Objective
To study the normal ranges of sleep–wake cycles in normal fetuses.
Materials and methods
A total of 600 fetal heart rate (FHR) tracings were studied from uncomplicated singleton pregnancies at a gestational age between 30 and 40 weeks with a 1-h recording. Two obstetricians interpreted all the FHR recordings independently.
Results
The mean baseline FHR was 141.6 (7.6) beats/min. The median relative percentage time spent in a quiet state was 26% (0–88.6). The median duration of time spent in a quiet state was 15.7 min (0–53.2) within a 1-h recording. Both quiet and active states were established in 84% of cases. The number of FHR accelerations per hour in an active state increased with advancing gestational age, whereas the baseline FHR gradually decreased.
Conclusions
Normal ranges of fetal sleep–wake cycles were established. Fetuses between 30 and 40 weeks had wide variations in the percentage of time spent in sleep–wake states.