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Published on: January 27, 2010
Chronobiology of labour pain perception: an observational study
A G M Aya1, N Vialles, R Mangin
1Division of Anesthesiology, Pain Management, Emergency and Critical Care Medicine, University Hospital, Nîmes, France. guy.aya@chu-nimes.fr
Background:
Circadian variation may affect many biological and pharmacological phenomena.
Methods:
To assess circadian variations in labour pain perception, 222 consecutive nulliparous women with uncomplicated pregnancy, spontaneous labour, cervical dilatation (3-5 cm), ruptured membranes and normal fetal heart rate tracings were studied. Visual analogue pain scores (VAPS) were analysed and divided into four periods: night (1:01 a.m. to 7:00 a.m.), morning (7:01 a.m. to 1:00 p.m.), afternoon (1:01 p.m. to 7:00 p.m.) and evening (7:01 p.m. to 1:00 a.m.). VAPS were also compared between daytime (morning+afternoon) and nocturnal (evening+night) periods.
Results:
Daytime mean VAPS were lower than nocturnal scores [75.6 (15.1) vs 85.7 (14.1), P<0.0001]. VAPS were lower in the morning than in the afternoon, evening and night periods (anova, P<0.0001).
Conclusion:
Labour pain perception appears to be chronobiological, and this might be taken into account when enrolling parturients in studies designed to assess or treat labour pain.
