Do obstetrics trainees working hours affect caesarean section rates in normal risk women?

The rate of caesarean section (CS) is increasing globally. The nulliparous, term, singleton, vertex presentation, spontaneously labouring woman (Robson Group 1/RG1) is considered low risk for CS. It has been hypothesized that more CS occur at nighttime or at weekends due to doctor fatigue. The European Working Time Directive (EWTD) was implemented in our institution in 2013 to limit doctor working hours, which aimed at reducing fatigue but arguably fractures continuity of care. This study aimed to determine the effect of nocturnal hours and weekend on-call as well as the implementation of EWTD on our RG1 CS rates.

This was a population-based study in a tertiary referral centre from 2008-2017. The inclusion criteria for our study were limited to RG1. Data were analysed from an established clinical database, including mode and time of delivery. Descriptive statistics are presented as number and percent for categorical variables. Relative frequencies were tested using chi-squared test. All statistical analyses were performed using SPSS Version 26. Statistical significance was defined as p < .05.

There were 86,473 deliveries over the 10-year study period. There were 18,761 women in RG1. Overall the RG1 CS rate was 12.9 % (n = 2415). Rates of CS in the RG1 were not statistically different between those delivering on weekdays (12.9 %, n = 1726/13,430) and weekends (12.9 %, n = 689/5,331, OR 0.99, 95 % CI = 0.90-1.09, p = .89). During daytime hours the CS rate was 12.1 % (n = 777/6411) and at nighttime was 13.3 % (n = 1638/12,350, OR 1.10, 95 % CI = 1.01-1.21, p = .03). Comparing the time periods pre and post EWTD implementation, there was a significant increase in CS rates (12.1 % n = 1319/10,873 V 13.9 % n = 1096/7,888, OR 1.17, 95 % CI = 1.07-1.27 p < .001). With respect to other modes of delivery in RG1 pre and post EWTD, there was a statistically significant decrease in operative vaginal delivery (OVD) rates (40.1%, n=4,360 V 37.7%, n=2,973, OR 0.90, 95% CI = 0.85-0.95, p = .001) CONCLUSION: This study shows an association between obstetric trainee working practices, RG1 CS and OVD rates; this is most pronounced at night and after the introduction of the EWTD. It is unlikely that obstetric trainee working practices are the only factor related to the increasing CS rate and reduced OVD rate. Consideration should be giving to addressing the needs of obstetric trainees in relation to achieving their competencies with now reduced labour ward exposure. Further study is required to see if alternate arrangements in relation to simulation training could increase the OVD rate and reduce the CS rate.