摘要Background Cesarean section births have been steadily increasing over the past decade and have become an epidemic in China.Cesarean delivery on maternal request is a major contributor to this upward trend,and there has been of much concern about its impact on maternal and child health.Most of mothers believe that cesarean delivery on maternal request can improve the child's intelligence,but direct evidence is sparse.In this cohort study,we aimed to directly assess the impact of cesarean delivery on maternal request on childhood intelligence.Methods Intelligence quotient (IQ) of 4144 preschool children from 21 cities/counties of Zhejiang and Jiangsu province whose mothers were registered in a population-based perinatal surveillance program during 1993-1996 was assessed with Chinese Wechsler Young Children Scale of Intelligence (C-WYCSI) in 2000.The outcomes were full-scale IQ,verbal IQ,and performance IQ of C-WYCSI.Mode of delivery and covariates were obtained from the surveillance program.We estimated unadjusted and adjusted effects of cesarean delivery on maternal request and assisted vaginal delivery on IQ scores compared with spontaneous vaginal delivery using regression analysis.Results The mean full-scale,verbal,and performance IQ for all children was 99.3±16.1,93.6±17.7,and 105.3±14.3.In crude analysis,cesarean delivery on maternal request versus spontaneous vaginal delivery was associated with an increase of 3.9 (95％ confidence interval,0.6 to 7.2) points in full-scale IQ,4.8 (1.2 to 8.4) points in verbal IQ,and 2.4(-0.6 to 5.3) points in performance IQ.After adjusting for maternal education,occupation,and IQ,the advantage was reduced to 1.6 (-1.3 to 4.5),2.3 (-0.8 to 5.5),and 0.6 (-2.0 to 3.3) points for full-scale,verbal,and performance IQ,respectively.Assisted vaginal delivery versus spontaneous vaginal delivery was not associated with IQ scores in any analysis.Conclusion Neither cesarean delivery on maternal request nor assisted vaginal delivery affected children's IQ.