Methods: Pregnant mothers in the first trimester, who presented to health clinics in Kuching, were screened. Mothers with existing diabetes mellitus or GDM were excluded using 75-g oral glucose tolerance test during the first and second trimesters. Participants with the first trimester BMI ≥ 23 kg/m2 were recruited as overweight/obese group, whereas those with BMI 18.5-22.9 kg/m2 were taken as the comparison group. At every trimester visit, mothers' weights were recorded. Babies' birth weight and occurrence of adverse neonatal outcome were documented.

Results: There were 123 mothers recruited as overweight/obese group (mean BMI 29.0 kg/m2 ± 4.45) and 102 mothers as comparison group (mean BMI 20.4 kg/m2 ± 1.48). The number of low birth weight was similar between groups: 9.8% in overweight/obese group, 6.9% in the comparison group (p = 0.416). More than half of these babies were born to mothers with inadequate GWG (58.3% in obese group vs. 57.1% in control group, p = 0.077). There was no significant difference in the mean birth weight (3000 g ± 454.5 vs. 3038 g ± 340.8, p = 0.471), preterm delivery (8.13% vs. 3.92%, p = 0.193), and admission rate to neonatal intensive care unit (8.13% vs. 7.85%, p = 0.937) between groups. There was a positive correlation between the total GWG in overweight/obese group on baby's weight (r = 0.222, p = 0.013). Inadequate GWG was not correlated with lower birth weight (p = 0.052).