OBJECTIVETo find out the occurrence of cesarean section (CS) and to probe the factors associated with CS.

METHODSWomen with CS as "case group" and women without CS as "control group" were chosen in a case-control study.

RESULTSAmong 14 071 childbirth women, 6 421 had CS (case group) with the occurrence rate of 45.6% and 7 650 (54.4%) had normal delivery (control group). In comparison with the control group, the CS group had following several higher rates [with significant differences between case group and control group (P < 0.01)]: well-educated (78.9% vs 69.5%), white collar jobs (38.0% vs 32.3%), urban residents (79.1% vs 70.6%), high monthly income (>/= 500 Yuan) (81.0% vs 70.6%), of older age (>/= 25 years) (73.3% vs 63.0%), heavier baby weight (> 4 000 gram) (8.3% vs 2.9%), male babies (53.9% vs 51.4%), BMI of mother (> 24) (8.8% vs 4.8%), cephalopelvic disproportion (21.1% vs 0.9%), intrauterine asphysia (20.3% vs 6.7%), abnormality of force of labor (4.2% vs 2.7%), prolonged labor (2.9% vs 1.0%) and placenta previa (1.4% vs 0.4%). Our study also indicated that the higher the educational level was, the higher the rate of CS appeared; and the older the pregnant women was, the higher the rate of CS was. In CS group, over 70% primipara were over 24 years, and over 20% primipara had cephalopelvic disproportion and over 20% had intrauterine asphysia in CS group.

CONCLUSIONSAt present, the occurrence rate of cesarean section was rather high (45.6%) in China. The high rate of CS was more likely to associate not only with abnormal physiological/medical factors (eg. cephalopelvic disproportion, intrauterine asphysia, abnormality of force of labor, and prolonged labour, etc.), but also with some demographic factors as education, occupation, income and age, etc. It is necessary to take measures to reduce the unnecessary CS in China.