Gestational weight gain, cesarean delivery, and cesarean delivery on maternal request: a cohort analysis of Chinese nulliparous women.

PURPOSE

To examine the association between gestational weight gain (GWG) and cesarean delivery including cesarean delivery on maternal request (CDMR) among low-risk women.

METHODS

A total of 1,009,987 Chinese nulliparous women who delivered live term singletons during 1993-2010 were included. GWG, according to maternal pre-pregnancy body mass index-specified z-scores, was categorized into five groups: less than -1.2, -1.2 to less than -0.6, -0.6 to 0.6 (reference), more than 0.6 to 1.2, and more than 1.2. Multivariate log-binomial regression models were used to estimate the adjusted risk ratios and 95% confidence intervals (95% CIs).

RESULTS

GWG was positively associated with overall cesarean and CDMR after adjusting for various confounders. Adjusted risk ratios for cesarean were 0.75 (95% CI, 0.73-0.77), 0.84 (95% CI, 0.82-0.85), 1.00, 1.16 (95% CI, 1.14-1.19), and 1.32 (95% CI, 1.29-1.35) in five ascending GWG categories, and 0.70 (95% CI, 0.67-0.73), 0.80 (95% CI, 0.78-0.82), 1.00, 1.20 (95% CI, 1.18-1.23), and 1.43 (95% CI, 1.40-1.45) for CDMR. The graded positive associations were consistent across levels of maternal pre-pregnancy body mass index, and in strata defined by southern and/or northern provinces, urban and/or rural residence, maternal age at delivery, year of delivery, and level of delivering hospital.

CONCLUSIONS

Even among low-risk women, higher GWG was monotonically associated with an increased risk of cesarean delivery, indicating that limiting GWG could benefit to curb the rate of both medically necessary and unnecessary cesareans.