·A total of 490 pregnant women admitted to one-day outpatient for GDM of The International Peace Maternity & Child Health Hospital, Shanghai Jiao Tong University School of Medicine from April 2018 to December 2019 were included. According to the energy contribution ratio of meals, they were divided into group A [207 cases, eggs were consumed at mid-morning snack (9:00), and the energy contribution ratio of breakfast and mid-morning snack was 15% and 10%, respectively] and group B [283 cases, eggs were consumed at breakfast (7:00), and the energy contribution ratio of breakfast and mid-morning snack was 20% and 5%, respectively], and the glycemic control levels of the group A and group B were compared. According to the difference of pre-pregnancy body mass index (BMI) and weight gain during pregnancy, after adjusting the dietary energy supply, pregnant women in the group B were further divided into group a (132 cases, no change in total energy) and group b (151 cases, total energy reduced by 1-2 exchange parts). The glycemic control level, body weight growth rate and pregnancy outcome were compared between the group a and group b.

·At 2 h after breakfast and before lunch, there was no significant difference between the blood glucose levels and standard values of pregnant women in the group A and group B. Compared with the group A, the blood glucose level of pregnant women in the group B before lunch had reached the control standard (< 5.60 mmol/L). After lunch, the blood glucose level of pregnant women in the group a was higher than the standard value (< 6.70 mmol/L) (P=0.009), but there was no significant difference between the group b and the standard value. The body weight gain rate of pregnant women in group b after intervention was lower than that before intervention (P=0.004). The incidence of gestational hypertension (P=0.015), premature delivery (P=0.032) and huge mass baby (P=0.032) in the group b was higher than that in the group a.

·Using 20% and 5% energy contribution ratio of breakfast and mid-morning snack for eating is helpful for GDM women to control the blood glucose levels before lunch. At the same time, appropriately reducing the intake of total energy is conducive to GDM women who are overweight or obese before pregnancy, or who gain too much weight during pregnancy to control the blood glucose levels and body weight growth rate after lunch, but they are still prone to adverse pregnancy outcomes. It is suggested that clinical intervention should be carried out as soon as possible.