Objectives: Improper gestational weight gain (GWG) causes many adverse obstetrical and neonatal outcomes. This study evaluates the relationship between weight gain in different phases and maternal outcomes or neonatal outcomes.

Material and methods: Finally, this study recruited 2,608 women delivered at Fujian Provincial Maternity and Child Health, affiliated hospital of Fujian Medical University from December 2017 to January 2019. To evaluate the relationship between maternal outcome and neonatal outcome, the participants were divided into four groups based on their baseline BMI and weight gain in the second/third trimester of pregnancy.

Results: This study demonstrated that neonate weight, small-for-gestational-age infants, macrosomia, neonatal death, cesarean delivery, and GDM significantly differed across the baseline BMI, weight gain in the second and third trimester. The umbilical cord's abnormality, bulging membrane, abruptio placentae, and postpartum hemorrhage were significantly related to baseline BMI. Furthermore, gestational hypertension and pre-eclampsia/eclampsia were significantly correlated with baseline BMI and weight gain in the second trimester. The maternal and infant outcomes are different, and the GWG curves are significantly different. Finally, multivariate regression analysis showed that baseline BMI and weight gain in the second/third trimester were the independent risk factors for GDM and macrosomia. Also, baseline BMI and weight gain in the third trimester were the independent risk factors for developing gestational hypertension and pre-eclampsia/eclampsia, respectively.

Conclusions: The baseline BMI and weight gain in the second/third trimester are significant with maternal outcomes and neonatal outcomes to a varying degree. Thus, maintaining appropriate baseline BMI and weight gain in different phases are essential in preventing pregnancy complications and maternal and neonatal prognosis.