///2018 Abstract Details
2018 Abstract Details2018-06-13T16:46:08+00:00

Cesarean Delivery Rate Is Not Influenced By Time Of Day

Abstract Number: S5B-5
Abstract Type: Original Research

Miguel Suarez MD1 ; Patsy McGuire MD2; Ghalia Al-Busayyes MD3; Virgil Manica MD4; Roman Schumann MD5; Dan Drzymalski MD6


Deciding to perform an unscheduled cesarean delivery (CD) is in part a subjective decision and may be influenced by non-obstetric factors such as the physician’s work hours or convenience.[1,2] Recognizing trends in CD rates may help hospitals to better allocate resources and decrease the risk of anesthesia-related adverse events.[3-5]

The aim of this study was to determine if a pattern exists in the timing of cesarean deliveries that might suggest non-obstetric factors influencing the decision to perform an unscheduled CD. Our hypothesis was that there would be an increased frequency of CD near the end of the obstetrician’s work shift.


Following IRB approval we performed a retrospective review of all deliveries that occurred in an urban academic tertiary care medical center during the year 2016. Maternal and neonatal data were gathered for all unplanned deliveries. CDs identified in an obstetric database as urgent, emergent or unplanned were all defined as unplanned CDs. The cesarean rate and hourly variation for all unplanned deliveries was determined for daytime (7:00-18:59) and nighttime (19:00-6:59) hours. The Chi-squared and the Mann-Whitney U tests were performed to analyze categorical variables and continuous variables, respectively. A multivariable logistic regression analysis was performed to determine factors that may influence unplanned CD. A p < 0.05 was considered significant and we used the Holm-Bonferroni correction for the multivariable analysis.


Out of a total of 1,373 deliveries that occurred during the study period, a total of 241 occurred by unplanned CD. There was no significant difference in the unplanned CD rate between daytime and nighttime hours (33.8% vs. 28.3%, odds ratio {OR} 1.35, [95% CI 0.95 – 1.89], p = .08). Figure 1 shows the hourly variation for unplanned cesarean deliveries. There was no statistically significant in the rates (p = 0.49). Factors that were significantly associated with unplanned cesarean deliveries included advanced maternal age (each year, OR=1.07, 95% CI [1.03 – 1.11], p = .0002), preterm labor (OR=2.92, 95% CI [1.62 – 5.67], p = .0007), and nulliparity (OR=1.64, 95% [1.16 – 2.41], p = .007).


The results of our study suggest that the decision to perform a CD in our academic center is not influenced by non-obstetric factors such as the obstetrician’s work hours. Instead, we found that clinical factors, including advanced maternal age, nulliparity, and preterm labor, were associated with a tendency towards having an unscheduled CD.


1. Burns et al. Med Care. 1995.

2. Fabbri et al. Health Policy. 2016.

3. Cheesman at al. Anesth Analg. 2009

4. Deneux-Tharaux et al. Obstet Gynecol. 2006

5. Davies et al. Anesthesiology. 2009

SOAP 2018