Background:
Small-for-gestational age is associated with higher morbidity and mortality as well as increased risk of metabolic disease in adulthood. However, management of GDM is largely focused on glycaemic control, with a view to reduce the occurrence of large-for-gestational-age (LGA) infants. Despite the clinical importance of SGA outcomes, risk factors for SGA delivery among women with GDM remains insufficiently understood.

Aim:
The primary aim of this study was to identify risk factors associated with having a SGA infant in GDM pregnancies.

Methods:
We conducted a retrospective audit of 425 GDM pregnancies resulting in live births at a single tertiary hospital between 1 February 2024 and 31 December 2024. The cohort consisted of 60% Asian (mean BMI 27.3), 20% Caucasian (mean BMI 33.3) and 19% Middle Eastern (mean BMI 29.9) women. Infants were classified as SGA if their birth weight was <10th percentile for gestational age and sex according to WHO growth standards. Multivariable logistic regression analysis was performed to identify independent risk factors associated with the delivery of a SGA newborn.

Results:
11.8% of women delivered SGA infants. A prior history of SGA was associated with a subsequent SGA baby (OR 17.09, P <0.001, 95% CI: 4.39-66.46). The first live born of a GDM pregnancy also had a higher association with SGA (OR 10.13, P 0.001, 95% CI: 2.71-37.86). Lower pre-pregnancy body mass index was associated with SGA in univariate analysis; but not after multivariable adjustment. Gestational weight gain, smoking, and oral glucose tolerance test values were not associated with SGA outcomes.

Discussion and Conclusion:
The strongest associations of a delivery of a SGA infant in this study was a prior history of a SGA infant and being the first live-born of a mother with GDM.