Secular trends in caesarean section rates over 20 years in a regional obstetric unit in Hong Kong

Although caesarean section rates have been increasing over the years in both public and private sectors in Hong Kong, there has been a paucity of formal surveys on local trends in such rates. This study aimed to examine the trends in caesarean section rates over a 20-year period at a public regional obstetric unit in Hong Kong using the Robson's Ten-group Classification System. All deliveries in a single obstetric unit during a 20-year period (1995-2014) were classified into 10 subgroups according to the Robson's classification. The annual caesarean section rate for each subgroup was calculated and then stratified into 5-year intervals to analyse any significant trends. The caesarean section rates in a total of 86 262 births with complete data were analysed. The overall caesarean section rate increased modestly from 15.4% to 24.6% during the study period. There was an obvious increasing trend for caesarean section in those with previous caesarean section (Robson's category 5), breech presentation at delivery (category 6 and 7), multiple pregnancy (category 8), and preterm labour (category 10). A gradual fall in caesarean section rate from 14.4% to 10.8% was seen in primiparous women with term spontaneous labour (category 1). Statistically significant differences (P