To investigate the correlation of pre-pregnancy body mass index and pregnancy weight gain on gestational diabetes mellitus(GDM).

A retrospective study was conducted in 545 pregnant women who were diagnosed with GDM and 295 non-diabetic pregnant women who were admitted from January to June in 2018.General clinical data such as age, height, pre-pregnancy weight, pre-delivery weight, and 75 g oral glucose tolerance test(OGTT) blood glucose level, family history of diabetes, pregnancy, and parity were collected, the correlation between pre-pregnancy body mass index and pregnancy weight gain and GDM of the two groups were compared.

There was no significant difference in age and height between GDM group and non-GDM group(P>0.05). The pre-pregnancy body mass index and gestational weight gain of pregnant women in GDM group and non-GDM group were(23.6±1.9) kg/m², (22.4±2.6) kg/m², (16.2±5.4) kg, (14.5±4.8) kg, respectively(P<0.001). The pre-pregnancy body mass, OGTT fasting blood glucose, OGTT 1 hour blood glucose and OGTT 2 hours blood glucose in the GDM group were significantly higher than those in the non-GDM group(P<0.001). The number of pregnant women with a family history of diabetes in the GDM group was significantly higher than that in the non-GDM group(P<0.001). The number of pregnant women in the GDM group was higher than that in the non-GDM group(P<0.05). Comparison of GDM incidence among pregnant women in the pre-pregnancy low body mass group, normal body mass group, super-recombinant group and obese group[18.2%(4/22), 61.7%(319/517), 73.5%(214/291) and 80.0%(8/10)]. With the increase of pre-pregnancy body mass index, the incidence of excess weight gain during pregnancy increased[36.4%(8/22), 43.1%(223/517), 73.5%(214/291), and 100%(10/10)], (P<0.001). The GDM incidence in the group without excess weight gain during pregnancy[54.6%(210/385)] was compared with that in the group with excess weight gain[73.6%(335/455)], (P<0.001). The pre-pregnancy body mass index[(23.6±2.2) kg/m²] of the group with excess weight gain during pregnancy was significantly higher than that of the group without excess weight gain during pregnancy[(22.6±2.1) kg/m²], (P<0.001). After adjusting for potential confounding factors such as family history of diabetes, gestational age, gestational age, pre-pregnancy body mass index, and gestational weight gain, it was found that low pre-pregnancy body mass was the protective factor of GDM, while overweight, obesity and overweight during pregnancy were the risk factors of GDM.

Overweight and obesity pre-pregnancy and excessive weight gain during pregnancy are risk factors for GDM.The increase in weight during pregnancy is associated with higher body mass index before pregnancy.

Pre-pregnancy body mass index; Weight gain; Gestational diabetes; Overweight; Obesity