Can the Day of the Week and the Time of Birth Predict the Mode of Delivery According to Robson Classification?

Worldwide, the cesarean section rate has steadily increased from 6.7% in 1990 to 21.1% in 2018 and is expected to rise even more. The World Health Organization propose the adoption of the Robson classification system as a global standard for monitoring, evaluating, and comparing delivery rates. The purpose of the current study is to use the Robson classification system to investigate how, independently of medical factors, the day of the week and time of delivery may be related to the mode of birth. In the sample analysis, we included the records of 8572 women giving birth in one private health facility in Greece. Over 60% of deliveries during the study period were performed by cesarean section, 30.6% by vaginal delivery, and 8.5% of deliveries were performed by operative vaginal delivery. The results of this study indicate that the lowest birth rates are observed on Monday, Saturday, and Sunday. Nulliparous women with no previous cesarean delivery, with a singleton in cephalic presentation ≥37 weeks with spontaneous labor (group 1) are 73% more likely to deliver by cesarean section between 08:00 A.M. and 03:59 P.M. compared to those who give birth between 12:00 A.M. and 07:59 A.M. Also, multiparous women with a single cephalic term pregnancy and one previous cesarean section (group 5.1) are 16.7 times more likely to deliver by cesarean section in the morning compared to overnight deliveries. These results point out two non-clinical variables that influences the CS rate. The Robson classification system was a useful tool for the above comparisons.