///2019 Abstract Details
2019 Abstract Details2019-07-13T07:45:15-05:00

Effect of Neuraxial Labor Analgesia on Circadian Rhythm of Labor: A Retrospective Cohort Study

Abstract Number: T210-543
Abstract Type: Original Research

Jie Zhou MD, MS, MBA, FASA1 ; Li Wang MD2; Gangli Guo MD3; Wenjie Qing MD4


The study of Varea et al revealed a clear circadian pattern of human births which was diurnal with a higher incidence of deliveries in the early morning in winter or morning in summer based on old delivery data of Casa de Maternidad in Madrid between 1887-1892. Bakker et al also suggested that induction of labor in the morning might improve outcomes. We performed this retrospective review to examine the circadian rhythm of labor and the impact of neuraxial labor analgesia (NLA).


27,826 delivery data from 1/1/2016 to 12/31/2017 at the Partners Healthcare Systems were collected, of which 17,165 vaginal deliveries were included. 13,722 parturients received NLA; 3,443 delivered naturally without NLA. Parturients were divided into 12 groups every 2 hours based on the baby delivery time of the day based on the Chinese celestial and sexagenary cycle system, as 23:00-1:00, 1:00-3:00, 3:00-5:00, 5:00-7:00...21:00-23:00. We analyzed delivery pattern as percentage during each time slot allocations, to determine the effect of circadian rhythm of labor in parturients with and without NLA.


Distribution of delivery time in spontaneous vaginal deliveries without NLA showed a diurnal pattern with a peak in the early morning between 3:00-5:00 at 9.8%, and the nadir between 15:00-17:00 at 6.9%. The birth time distribution showed a sinusoidal pattern of parturients who delivery without NLA. The distribution of birthing times of parturients with NLA were significantly different. (P<0.001) (Figure 1)


Interestingly, our study demonstrated similar sinusoidal birthing time as Varea et al in parturients with delivered naturally without NLA. Administration of NLA obscured the natural diurnal birthing pattern. This was a preliminary analysis of our data with an intention to mimic the presentation of Varea et al. We are planning on secondary analysis by addition of parity data and other relevant factors in order to better understand the onset and progress of labor process.


1. Varea C, et al. Am J Hum Biol 2014;26:707

2. Bakker JJ, et al. Cochrane Database Syst Rev 2013;28:CD007707

3. Arendt K, et al. Anesth Analg 2008;107:2096

SOAP 2019