Abstract:

Objective Based on the body mass index (BMI) classification of Chinese population and the latest recommended range of gestational weight gain by the Chinese Nutrition Society, this study aims to evaluate the pre-pregnancy BMI and gestational weight gain status of pregnant women and further explored explore their influence on neonatal birth outcomes. Methods A total of 26 422 pregnant women who received regular prenatal examination were selected from January 2018 to December 2019 were included. The pre-pregnancy BMI, gestational weight gain of the study subjects, and their demographic characteristics among subgroups were described. Univariate and multivariate binary logistic regression analyses were employed to investigate the relationships between pre-pregnancy BMI and gestational weight gain and various neonatal outcomes (such as macrosomia, low birth weight, preterm birth, and asphyxia). Finally, a heatmap was utilized to explore the combined effect of pre-pregnancy BMI and gestational weight gain on fetal weight. Result The study found that the proportions of underweight and overweight/obese pregnant women were 13.8% and 14.7%, respectively, indicating a similar distribution. More than 50% of the participants experienced abnormal gestational weight gain. Insufficient gestational weight gain was associated with an increased risk of preterm birth. A low pre-pregnancy BMI or insufficient gestational weight gain elevated the risk of small for gestational age (SGA), whereas a high pre-pregnancy BMI or excessive gestational weight gain increased the risk of large for gestational age (LGA) and dystocia (cesarean section, forceps/vacuum extraction) (P<0.05). Multivariate analysis did not reveal a significant association between pre-pregnancy BMI, gestational weight gain, and neonatal asphyxia (P>0.05). Conclusion Abnormal gestational weight gain remains a significant issue among pregnant women, suggesting that obstetric healthcare providers and society need to strengthen the dissemination of pregnancy knowledge and weight management for pregnant women. In clinical practice, heatmaps can be utilized to assess individual risks of abnormal fetal weight and dystocia, thereby reducing adverse outcomes.

Key words: pre-pregnancy body mass index, gestational weight gain, neonatal birth outcomes, heatmap