20-year trend in Caesarean section rates in primiparous women in a regional obstetric unit in Hong Kong Abstract

Introduction: Using the Robson classification, we analysed the 20-year trend of Caesarean section (CS) rates among primiparous women in a regional obstetric unit in Hong Kong.
Methods: Deliveries over a 20-year period (1997-2016) from United Christian Hospital were classified into one of 10 categories according to the Robson classification. The annual CS rate was calculated for each category, and data were stratified into four 5-year intervals to determine any trends.
Results: A total of 86 908 deliveries from 1997 to 2016 were included for analysis. The overall CS rate increased from 17.5% to 23.5% over the period. However, the overall primiparous CS rate only increased modestly from 20.8% to 22.8%, with main contributors being breech presentation (category 6), multiple pregnancies (category 8), and preterm labour (category 10). Contrarily, the CS rate declined mildly among those with spontaneous and induced labour (category 1 and 2). These trends were significant (p<0.001) after stratification into four 5-year intervals.
Conclusion:Despite a sharper rise in overall CS rate over the past 20 years, the CS rates in primiparous women increased modestly, mainly because of modest increases in rates of breech presentation, multiple pregnancies, and preterm labour.