Relationships Between Exposure to Gestational Diabetes Treatment and Neonatal Anthropometry: Evidence from the Born in Bradford (BiB) Cohort.

OBJECTIVES: To examine the relationships between gestational diabetes mellitus (GDM) treatment and neonatal anthropometry. METHODS: Covariate-adjusted multivariable linear regression analyses were used in 9907 offspring of the Born in Bradford cohort. GDM treatment type (lifestyle changes advice only, lifestyle changes and insulin or lifestyle changes and metformin) was the exposure, offspring born to mothers without GDM the control, and birth weight, head, mid-arm and abdominal circumference, and subscapular and triceps skinfold thickness the outcomes. RESULTS: Lower birth weight in offspring exposed to insulin (- 117.2 g (95% CI - 173.8, - 60.7)) and metformin (- 200.3 g (- 328.5, - 72.1)) compared to offspring not exposed to GDM was partly attributed to lower gestational age at birth and greater proportion of Pakistani mothers in the treatment groups. Higher subscapular skinfolds in offspring exposed to treatment compared to those not exposed to GDM was partly attributed to higher maternal glucose concentrations at diagnosis. In fully adjusted analyses, offspring exposed to GDM treatment had lower weight, smaller abdominal circumference and skinfolds at birth than those not exposed to GDM. Metformin exposure was associated with smaller offspring mid-arm circumference (- 0.3 cm (- 0.6, - 0.07)) than insulin exposure in fully adjusted models with no other differences found. CONCLUSIONS FOR PRACTICE: Offspring exposed to GDM treatment were lighter and smaller at birth than those not exposed to GDM. Metformin-exposed offspring had largely comparable birth anthropometric characteristics to those exposed to insulin.