The altered intrauterine environment of gestational diabetes mellitus (GDM) can affect fetal growth and development. Body composition is used to characterize overgrowth, with increases in fat mass apparent in infants of GDM pregnancies. This cross-sectional study was performed to determine body composition and anthropometric measurements at birth in term infants of women with GDM compared with infants of mothers with normal glucose tolerance (NGT) levels.
In singleton, term infants, with no congenital anomalies, the diagnosis of maternal GDM was based on the Australasian Diabetes in Pregnancy Society criteria. Mothers with GDM self-monitored and recorded their blood glucose levels 4 times a day. Neonatal anthropometric measurements were made within 48 hours of birth. Neonatal body fat percentage, fat mass, and fat-free mass were assessed by air-displacement plethysmography. The associations between GDM status and neonatal body fat % and fat-free mass and other anthropometric measurements were investigated using linear regression. The association between neonatal body fat% and maternal glycemic indices in the GDM group was assessed using correlation coefficients.
Of 815 mothers and their infants, the final study cohort included 532 and 67 patients in the NGT and GDM groups, respectively. The groups did not differ significantly in maternal age (GDM, 33.2 ± 4.7 years; NGT, 32.5 ± 5.1 years; P = 0.22). Mothers with GDM were more likely to be overweight or obese (36% vs 22%; P = 0.011). Good glycemic control was achieved in 56 (90%) of 62 women meeting both fasting and postprandial glycemic targets. The mean third-trimester HbA1c for the whole GDM group was 5.4 ± 0.4 mmol/L. Self-monitoring data for 46 women (mean, 132 readings/patient) showed mean blood glucose levels of 4.8 ± 0.5 mmol/L fasting, 6.7 ± 1.1 mmol/L 1 hour after breakfast, 6.4 ± 0.7 mmol/L after lunch, and 6.5 ± 0.7 mmol/L after dinner. After adjusting for gestational age, neonatal sex, and maternal variables that affect body composition, no significant differences in body fat % were found between the GDM and NGT infants (mean difference, −0.85 [95% confidence interval, −2.00 to 0.31]; P = 0.151). The GDM and NGT infants did not differ significantly in birth weight and other anthropometric measurements.
These results show that normal neonatal body composition can be achieved in infants born to mothers with GDM with good glycemic control. Neonatal body fat% was normalized in the setting of good glycemic control. Thus, early detection and treatment of GDM may help prevent neonatal overgrowth, a factor strongly related to childhood obesity and diabetes. Future work will involve a follow-up of this cohort to evaluate long-term outcomes.
Sydney Medical School (C.P.A., H.E.J.), University of Sydney, Sydney; Sydney School of Public Health (C.P.A., A.E.C., C.H.R.-G., H.E.J., R.M.T.), University of Sydney, Sydney; and Royal Prince Alfred Hospital Newborn Care (H.E.J.), Sydney, Australia