Abstract:Abstract: OBJECTIVE To investigate the pre-pregnancy BMI and Gestational Weight Gain (GWG) status of pregnant women in Lingshan County and its impact on newborn birth weight. METHODS From September 2022 to June 2023, 1 292 pregnant women who registered and delivered at the Lingshan County Maternal and Child Health Hospital in Guangxi Zhuang Autonomous Region were selected as the study subjects. Pregnant women were grouped based on pre-pregnancy BMI and GWG, and the impact of pre-pregnancy BMI on GWG and the impact of pre-pregnancy BMI and GWG on newborn birth weight were investigated under different conditions. Quantitative data were analyzed using analysis of variance, and qualitative data were analyzed using χ 2 tests or Fisher exact probability method. RESULTS There were 242 cases of pre-pregnancy overweight/obesity (18.7% ), 269 cases of pre-pregnancy underweight (20.8% ), 144 cases of inadequate GWG (11.2% ), and 505 cases of excessive GWG (39.0% ). The proportion of inadequate GWG among pre-pregnancy underweight women was 20.8%, while the proportion of excessive GWG among pre-pregnancy overweight/obese women was 45.0% . Regarding newborns, the proportion of low birth weight infants in the pre-pregnancy underweight group was 6.7% , while the proportion of macrosomia in the excessive GWG group was 4.4% , and the proportion of low birth weight infants in the inadequate GWG group was 9.0% . CONCLUSION The issues of pre-pregnancy underweight, excessive GWG, and low birth weight newborns are more prominent in Lingshan County. Compared to pre-pregnancy BMI, GWG has a more significant impact on newborn birth weight.