Evaluating the effect of gestational diabetes mellitus on macrosomia based on the characteristics of oral glucose tolerance test

Background: GDM is always treated as a homogenous disease ignoring the different metabolic characteristics in oral glucose tolerance test (OGTT). We assessed the effect of GDM on macrosomia based on the different characteristics of OGTT.

Methods: We retrospectively divided 998 GDM pregnant women into 7 groups, Group A1: abnormal OGTT_0h; Group A2: abnormal OGTT_1h; Group A3: abnormal OGTT_2h; Group B1: abnormal OGTT_0h+1h; Group B2: abnormal OGTT_0h+2h; Group B3: abnormal OGTT_1h+2h; Group C: abnormal OGTT_0h+1h+2h.

Results: The incidence of macrosomia in group C (21.92%) was higher than other groups. The OR of OGTT_0h+1h+2h was significant (OGTT_1h: OR = 1.577, 95% CI: 0.791, 3.145; OGTT_2h: OR = 1.151, 95% CI: 0.572, 2.313; OGTT_0h+1h: OR = 1.346, 95% CI: 0.584, 3.101; OGTT_0h+2h: OR = 1.327, 95% CI: 0.517, 3.409; OGTT_1h+2h: OR = 0.771, 95% CI: 0.256, 2.322; OGTT_0h+1h+2h: OR = 4.164, 95% CI: 2.095, 8.278) when comparing with OGTT_0h. Subgroup analysis showed abnormal OGTT_0h+1h+2h might contribute more to macrosomia in pre-pregnancy BMI ≥ 24 kg/m² than those with BMI < 24 kg/m².

Conclusion: The effect of abnormal OGTT_0h+1h+2h on macrosomia was significantly greater than other OGTT characteristics, especially for those with pre-pregnancy BMI ≥ 24 kg/m². Individualized management of GDM based on OGTT characteristics and pre-pregnancy BMI might be needed.