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Published on: October 24, 2019
Sleep-wake cycles in normal fetuses
Chitkasaem Suwanrath1, Thitima Suntharasaj
1Department of Obstetrics and Gynecology, Prince of Songkla University, Hat Yai, Songkhla 90110, Thailand. schitkas@yahoo.co.uk
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.
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