Use of the 10-Group Classification System to analyze how the population control policy change in China has affected cesarean delivery.

<bold>Objective: </bold>To analyze the initial effect following the relaxation of China's population control policy on the cesarean delivery (CD) rate using the 10-Group Classification System (TGCS).<bold>Methods: </bold>A retrospective study included all deliveries at a center in Nanjing, China, during 2014-2015. The deliveries were classified using the TGCS. The obstetric populations and the CD rates in each group were compared between 2014 and 2015.<bold>Results: </bold>Overall, 11 006 deliveries were analyzed. The overall CD rate increased from 28.3% (1623/5737) in 2014 to 33.8% (1782/5269) in 2015 (P<0.001). The largest contributor to the overall CD rate-accounting for approximately one-third of all CDs-were nulliparous women with a single cephalic term pregnancy and induced labor or prelabor CD (group 2); the CD rate in this group increased from 27.2% to 31.4%. Moreover, the proportion of women with a single cephalic term pregnancy with previous CD (group 5) steeply increased from 6.4% to 10.4% of all deliveries; the CD rate in this group during 2014-2015 was 76.6%.<bold>Conclusion: </bold>With China ending its one-child policy, the characteristics of the obstetric population changed. Women with a single cephalic term pregnancy with previous CD were the largest contributor to the CD rate increase. [ABSTRACT FROM AUTHOR]