Obstetric Outcomes of Nighttime Versus Daytime Delivery with Labor Epidural: An Observational Retrospective Study.

Background : Variability in obstetric outcomes in terms of the number and type of deliveries related to the day-night cycle has been described in previous studies. This 11-year retrospective analysis explores the effects of nighttime versus daytime delivery with labor epidural on obstetric outcomes. Methods : Data on deliveries performed between 1 October 2008 and 1 October 2019 were collected and differentiated into daytime, occurring from 8:00 a.m. to 7:59 p.m., and nighttime deliveries, occurring from 8:00 p.m. to 7:59 a.m. of the following day. The data collected included the patient history and maternal and neonatal outcomes. Results : A total of 29831 patients were included in the analysis. A positive and statistically significant correlation between the number of cesarean sections (Odds Ratio 1.35; 95% confidence interval = 1.26-1.44; p < 0.001) and the number of vaginal operative deliveries (Odds Ratio 1.21; 95% confidence interval = 1.01-1.44; p < 0.05) in patients who did not receive an epidural at nighttime was reported. Regarding the labor epidurals, a significantly greater incidence of accidental dural punctures with needles (0,4%; p < 0.05) in the nighttime versus daytime was reported. Conclusions : The absence of labor epidurals was associated with a significant increase in the number of cesarean sections and vaginal operative deliveries occurring at nighttime, without significant differences in labor duration. The incidence of anesthesiologic complications was greater in deliveries performed at nighttime.