Effects Of Pre-pregnancy Body Mass Index And Gestational Weight Gain On Glucose Metabolism And Maternal And Infant Outcomes In Patients With Gestational Diabetes Mellitus

Objective To investigate the effects of different pre-pregnancy body mass index（BMI）and gestational weight gain（GWG）on glucose metabolism and pregnancy outcomes in pregnant women with gestational diabetes mellitus（GDM）.Methods Clinical data of 1667 pregnant women with GDM diagnosed in the Department of Obstetrics and Gynecology of the Sixth Medical Center of PLA General Hospital from January 2019 to December 2021 were collected and analyzed retrospectively.According to the pre-pregnancy BMI,all GDM pregnant women were divided into four groups:There were 132 cases in wasting group（BMI<18.5 kg/m²）,1044 cases in normal group（18.5 kg/m²≤BMI<24 kg/m²）,373 cases in overweight group（24 kg/m²≤BMI<28kg/m²）and 118 cases in obesity group（BMI≥28 kg/m²）.The levels of Hb A_1c,OGTT-FPG,OGTT-1h,OGTT-2h,FIN,HOMA-IR,HOMA-βand neonatal birth weight were compared among the four groups.Logistic regression was used to analyze the association between pre-pregnancy BMI and maternal and infant outcomes.According to the degree of gestational weight gain（GWG）,all GDM pregnant women were divided into three groups:There were 882 cases in the GWG below group,566 cases in the GWG within group,and 219 cases in the GWG above group.Hb A1c,OGTT-FPG,OGTT-1h,OGTT-2h,FIN,HOMA-IR,HOMA-β,and neonatal birth weight were compared among the three groups.Logistic regression was used to analyze the correlation between GWG and maternal and infant outcomes.Results According to pre-pregnancy BMI grouping,the levels of Hb A_1c,OGTT-FPG,OGTT-1h,FIN,HOMA-IR and HOMA-βin the overweight and obese groups were significantly higher than those in the thin and normal BMI groups（P<0.05）.Compared with the thin and normal BMI groups,the overweight and obesity groups had significantly lower GWG（P<0.05）,but the proportion of excessive GWG in the overweight and obesity groups was significantly higher than that in the thin and normal BMI groups（P<0.05）.The birth weight of the newborns in the obesity and overweight groups were significantly higher than that in the thin and normal BMI groups（P<0.05）.The incidence of cesarean section,HDP,LGA and SGA in GDM women with four pre-pregnancy BMI groups were statistically different（P<0.05）,and were positively correlated with pre-pregnancy body mass index.Logistic regression analysis showed that BMI during pregnancy was an independent risk factor for HDP,macrosomia,LGA and SGA（P<0.05）.According to the degree of GWG,the levels of Hb A_1c,FPG,FIN,HOMA-IR and HOMA-βin the GWG above group were significantly higher than those in the GWG below group and GWG within group（P<0.05）.The GWG below group had significantly lower levels of FIN,HOMA-IR,and HOMA-βthan the GWG within group（P<0.05）.The neonatal birth weight in the GWG above group was significantly higher than that in the GWG below group and GWG within group（P<0.05）,while the neonatal birth weight in the GWG below group was significantly lower than that in the GWG within group（P<0.05）.Excessive weight gain during pregnancy increased hypertensive disorders complicating pregnancy（OR 1.83,95%CI1.03～3.26）,macrosomia（OR 1.78,95%CI 1.08～2.95）and large for gestational age（OR 1.94,95%CI 1.08～2.95）.95%CI 1.26-2.99)（P<0.05）.Logistic regression analysis showed that both GWG above and GWG below were independent risk factors for HDP,macrosomia,and LGA（P<0.05）.Conclusions The lower the pre-pregnancy BMI,the higher the probability of vaginal delivery in GDM women.On the contrary,the higher the pre-pregnancy BMI,the higher the probability of cesarean section.The higher the pre-pregnancy BMI or GWG,the higher the levels of Hb A_1cat 6-12 weeks of pregnancy,OGTT-FPG,OGTT-1h and FIN at 24-28 weeks of pregnancy.In addition,HOMA-IR and HOMA-βlevels increased significantly with the increase of pre-pregnancy BMI or gestational weight gain,which may be closely related to the occurrence of enhanced insulin resistance during pregnancy.Pre-pregnancy obesity can significantly increase the birth weight of newborns;In addition,higher pre-pregnancy BMI increased the risk of HDP,macrosomia and LGA,but decreased the risk of SGA.The higher the degree of gestational weight gain,the higher the probability of cesarean section and the lower the probability of vaginal delivery in GDM women.The more GWG during pregnancy,the greater the neonatal birth weight.Excessive weight gain during pregnancy increases the risk of HDP,macrosomia and LGA.Reasonable weight management before and during the second and third trimesters of pregnancy can improve pregnancy outcomes and reduce the incidence of maternal and infant complications,so as to further ensure the safety of mothers and infants.