Maternal hypertriglyceridemia: A link between maternal overweight-obesity and macrosomia in gestational diabetes

Objective: Infants born from overweight and obese mothers with glucose-controlled gestational diabetes (GDM) tend to be large-for-gestational age (LGA). It is hypothesized that this is due to an excessive rise in maternal triglyceride levels. Methods: Two-hundred and seventy nine singleton GDM pregnancies were divided into three groups according to prepregnancy BMI: normal weight (BMI = 20-24.9; n = 128), overweight (BMI = 25-29.9; n = 105), and obese (BMI ≥ 30; n = 46). Individual z-scores (ZS) of maternal triglycerides and of newborn weight (NWZS) were calculated as deviations from published 50th percentiles. Mean z-scores (MZS) were the average of triglyceride ZSs. MZS of triglycerides, HbA1c and NWZS were compared. Variables are expressed as mean ± SD. Results: In the three groups respectively: LGA (%) = 10.1%, 19.0% and 30.4% (P = 0.015). Birth weight (g) = 3274.2 ± 501.3, 3342.4 ± 620.2 and 3366.3±644.7 (RSPEARMAN= 0.111, P = 0.027). HbA1c (%) = 5.2 ± 0.39, 5.3 ± 0.50 and 5.4 ± 0.47 (P = NS). Triglyceride MZS = 1.20 ± 1.13, 1.52 ± 1.37 and 1.62 ± 1.42 (RSPEARMAN= 0.116, P = 0.024). Correlations between triglyceride MZS and NWZS were, respectively: r = 0.12 (P = NS), r = 0.42 (P <0.001), and r = 0.47 (P < 0.001). Conclusions: In overweight and obese GDM mothers, maternal triglycerides are partially responsible for LGA infants despite good maternal glucose control during pregnancy.