Epidemiological characteristics of gestational weight gain among Chinese pregnant women and its association with adverse pregnancy outcomes in 24 medical institutions across 18 provinces

Objective To explore the epidemiological characteristics and influencing factors of gestational weight gain (GWG) among Chinese pregnant women, and to analyze the association between GWG and adverse pregnancy outcomes.

Methods This retrospective cohort study included low-risk pregnant women and their newborns delivered between September 1 and October 31, 2019, at 24 hospitals across 18 provinces (municipality, autonomous region) in China. The participants were divided into 4 groups of underweight, normal weight, overweight, and obesity based on their pre-pregnancy body mass index (BMI), and 7 groups of north, northeast, central, east, south, southwest, and northwest China based on region, respectively. Multivariable linear regression was used to identify the influencing factors of GWG. Multivariable logistic regression was used to analyze the association between GWG and the occurrence of adverse pregnancy outcomes.

Results A total of 9 075 pregnant women were included in this study. The percentage of pre-pregnancy underweight, normal weight, overweight and obese pregnant women were 17.1% (1 549/9 075), 66.4% (6025/9 075), 13.7% (1 245/9 075), and 2.8% (256/9 075), respectively. Age, pre-pregnancy BMI, education level, and parity were negatively associated with GWG. The geographical distribution of GWG was characterized by "high in the north and low in the south". With north China as the reference, there was higher GWG in northeast and northwest China, and lower GWG in central, east, south and southwest China. GWG was positively associated with the risk of cesarean section in large for gestational age infants, but negatively correlated with the risk of cesarean section in small for gestational age infants.

Conclusion GWG was influenced by maternal individual characteristics. Both pre-pregnancy BMI and GWG were significantly higher in the north and lower in the south in the surveyed population. GWG was significantly associated with various adverse perinatal outcomes. Therefore, it is essential to take into account the epidemiological characteristics of GWG when formulating appropriate GWG recommendations in China, so as to establish a more scientific and reasonable recommended range of GWG. In addition, it is necessary to scientifically adjust the dietary structure, promote appropriate exercise, and manage GWG in order to reduce the risk of adverse pregnancy outcomes.