[Optimal gestational weight gain for Chinese urban women]

Objective: To examine optimal gestational weight gain(GWG) for Chinese pregnant women.

Methods: A total of 6998 women with singleton and term pregnancy recruited to the Tongji Maternal and Child Health Cohort during January 2013 to May 2016 in Wuhan, Hubei were included. Information on sociodemographic, medical and family history of disease was obtained by questionnaire, body weight and height were measured at the first antenatal care during 8-16 weeks of gestation. Prenatal weight of mothers were measured, and gestational week, mode of delivery, pregnancy complications, gender of newborn, birth weight and length were collected from medical records after delivery. Restricted cubic spline was used to model nonlinear relationships between GWG and the occurrence of small for gestational age(SGA), large for gestational age(LGA), low birth weight(LBW), macrosomia, cesarean, gestational hypertension(GH)and gestational diabetes mellitus(GDM), respectively. The GWG of the lowest risks for adverse pregnant outcomes was regarded as optimal GWG recommended by Tongji(TJ) for pregnant women. The P25-P75 of GWG was defined as the optimal GWG recommended by percentile method. Logistic regression was used to analyze the effect of excessive or insufficient GWG on adverse pregnancy outcomes, while the recommendations of TJ and percentile method were used as references, respectively.

Results: (1) The GWG with lower risk of adverse pregnant outcomes based on pre-gravid body mass index(BMI) are 12. 0-17. 0 kg for underweight, 9. 0-14. 0 kg for normal weight and 7. 0-11. 0 kg for overweight, respectively, which are defined as TJ recommendations. The recommended GWG by percentile method are 14. 0-19. 0 kg for underweight, 13. 0-19. 0 kg for normal weight, 10. 8-18. 0 kg for overweight and 9. 0-15. 8 kg for obesity, respectively. (2) Compared to women gain within the TJ recommendations, OR of LGA is 2. 94(95%CI 2. 31-3. 73), macrosomia is 3. 13(95%CI 2. 38-4. 13), cesarean is 1. 53(95%CI 1. 38-1. 71) and GH is 2. 18(95%CI 1. 50-3. 17) for those with excessive GWG, OR of SGA is 1. 82(95%CI 1. 32-2. 53) for those who gain less. The corresponding ORs according to percentile method are 2. 11(95%CI 1. 76-2. 54) for LGA, 2. 16(95%CI 1. 76-2. 65) for macrosomia, 1. 53(95%CI 1. 36-1. 72) for cesarean, 1. 39(95%CI 1. 02-1. 90) for GH and 1. 60(95%CI 1. 29-1. 99) for SGA, respectively.

Conclusion: The optimal GWG of Chinese pregnant women recommended by the study are 12. 0-17. 0 kg for pre-gravid underweight women, 9. 0-14. 0 kg for normal weight women and 7. 0-11. 0 kg for overweight, respectively.