Associations between maternal gestational diabetes metformin or insulin treatment and offspring growth trajectories from birth to 60months of age: Findings from the Born in Bradford (BiB) study

AimTo investigate the associations between gestational diabetes mellitus (GDM) metformin or insulin treatment and offspring growth trajectories from 0 to 60 months.MethodsParticipants were from the Born in Bradford birth cohort study. Using covariate‐adjusted multilevel linear spline models (4 splines: 0–1.6, 1.6–6, 6–17 and 17–60 months), we compared weight, height and body mass index (BMI) z‐score trajectories of: (1) 76 offspring exposed to metformin (OGDM‐Metformin) and 420 offspring exposed to insulin (OGDM‐Insulin); (2) OGDM‐Metformin and 9171 offspring not exposed to GDM (No‐GDM); (3) OGDM‐Insulin and No‐GDM.Results(1) OGDM‐Metformin had comparable growth trajectories to OGDM‐Insulin from 0 to 60 months. (2) OGDM‐Metformin had a lower mean birthweight z‐score than No‐GDM. OGDM‐Metformin had faster changes in height z‐score (0.13 [95% CI 0.026, 0.24]) from 17 to 60 months and by 60 months, had comparable mean BMI z‐score to No‐GDM. (3) OGDM‐insulin had lower mean birthweight and height z‐scores than No‐GDM. OGDM‐Insulin had faster changes in weight (0.32 [0.021, 0.62]) and height (0.50 [0.087, 0.91]) from 1.6 to 6 months and by 60 months, had comparable mean BMI z‐score to No‐GDM.ConclusionsGDM metformin treatment was not associated with differences in offspring growth trajectories compared to insulin treatment. Both metformin and insulin‐exposed offspring had comparable BMI z‐score to No‐GDM by 60 months.