The effects of China-recommended gestational weight gain guidelines and the Institute of Medicine guidelines on adverse birth outcomes: A population- based cohort study.

Objectives: This study aimed to assess and compare the Institute of Medicine (IOM) guidelines and the recently published China guidelines regarding their applicability for gestational weight gain (GWG) management among Chinese pregnant women.

Method: Data were extracted from the Electronic Medical Record System of Zhoushan, China. Adverse outcomes include small for gestational age (SGA), large for gestational age (LGA), low birth weight and macrosomia. GWG were estimated by the China and IOM GWG guidelines, respectively. Multiple logistical regression models were used to analyze the associations of GWG with outcomes. The modified guidelines were developed.

Results: Among 9975 pregnant women without comorbidities (i.e., gestational diabetes mellitus and pregnancy-induced hypertension), comparing women with normal GWG in both guideline, those with insufficient GWG in the IOM guidelines but normal GWG in the China guidelines were more likely to delivery infants with SGA (aOR = 1.38; 95% CI: 1.07, 1.79); while those with normal GWG in the IOM guidelines but excessive GWG in the China guidelines had an increased risk of LGA (aOR = 1.49; 95% CI: 1.12, 1.98) and macrosomia (aOR = 1.70; 95% CI: 1.11, 2.60). Similar results weren't observed among 4438 pregnant women with comorbidities. The modified guidelines were developed by combining the weekly GWG targets from the IOM (bottom values) and the China guidelines (upper values). The modified guidelines with Chinese BMI cut-off points exhibited the highest sensitivity for all adverse outcomes.

Conclusion: The China guidelines would better recognize pregnant women at risk of LGA and macrosomia but overlook a subgroup of women at risk of SGA, as recognized by the IOM guidelines. These disparities emphasized neither guidelines may be entirely suitable for GWG management in China. The modified guideline would be more appropriate for Chinese pregnant women, but further validation through research is needed.