Maternal Obesity, Caesarean Delivery and Caesarean Delivery on Maternal Request: a Cohort Analysis from China
Paediatric and Perinatal Epidemiology. 2015, 29, 232–240.
Y Zhou, J Blustein, H Li, R Ye, L Zhu, J Liu
Background—To quantify the association between maternal obesity and cesarean delivery, particularly cesarean delivery on maternal request [CDMR], a fast-growing component of cesarean delivery in many nations around the world.
Methods—We follow 1 187 053 women registered in the Perinatal Healthcare Surveillance System during 1993-2010. Maternal body mass index (BMI, Kg/m2), before pregnancy or during early pregnancy, was classified as underweight (BMI <18.5), normal (BMI 18.5~<23; reference), overweight (BMI 23~<27.5), or obese (³27.5), consistent with WHO guidelines for Asian people. The association between maternal obesity and overall cesarean delivery and its subtypes was modeled using log binomial regression.
Results—During the 18-year period, 450 436 (37.9%) cesarean deliveries and 103 723 (8.7%) CDMRs were identified. Maternal obesity was positively associated with overall cesarean and CDMR. Adjusted risk ratios for overall cesarean in the four ascending maternal BMI categories were 0.95, 1.00, 1.17, 1.40 [corresponding 95% confidence intervals (CIs): 0.94, 0.96; 1.00; 1.15, 1.18; 1.35, 1.44; P <0.001 for trend], and adjusted risk ratios for CDMR were 0.94, 1.00, 1.20, 1.47 [corresponding 95% CIs: 0.93, 0.96; 1.00; 1.19, 1.22; 1.43, 1.51; P<0.001 for trend]. Positive associations were consistently found in subgroups stratified by maternal age, education, rural or urban residence, level of delivering hospital, year of delivery, birthweight, and parity.
Conclusions—In a large prospective Chinese cohort, maternal obesity was associated with an increased risk of cesarean delivery and its subtypes, including CDMR. Given the rising global prevalence of obesity, and in view of the growth of CDMR, it seems likely that cesarean births will increase, absent changes in obstetrical practice