Background: In the MiTy trial [pregnant T2D randomized to metformin vs. placebo], infants exposed to metformin in-utero had a lower risk of large-for-gestational-age (LGA) but were at higher risk of small-for-gestational-age (SGA) . To date, there are limited data on the effect of in-utero exposure to metformin on infant/child growth in T2D, according to the intrauterine growth status. The MiTy Kids study followed the offspring of MiTy participants to 24 months of age to examine the effect of metformin exposure in-utero on child growth.

Aim: Examine the weight and body mass index (BMI) trajectories of children of women with T2D, according to the intrauterine growth status [appropriate for gestational age (AGA) , LGA, and SGA] and metformin exposure.

Methods: The study population included offspring of MiTy trial participants. Height and weight measurements were collected at 3, 6, 12, 18 and 24 months of age. Analysis of data was conducted using a fractional polynomial linear mixed effects approach to compare growth trajectories.

Results: Of the 283 children who participated in MiTy Kids (46.3% female) , 194 children were AGA at birth (90 metformin and 1placebo) , 65 were LGA (29 metformin and 36 placebo) , and 24 were SGA (16 metformin and 8 placebo) . In children born AGA, both sexes in the metformin arm had a lower weight gain trajectory than those in the placebo group (p=0.008) . Treatment and sex did not have an effect on the growth trajectories of children born LGA. In SGA children, in both sexes, SGA children in the metformin group had a lower weight gain trajectory (p=<0.001) and BMI trajectory (p=0.042) than children in the placebo group, and achieved a lower weight than the WHO growth standard at 24 months.

Conclusion: Metformin exposure in-utero was associated with lower weight gain trajectories and BMI trajectories in children of both sexes born SGA and lower weight gain trajectory in AGA children. Further follow-up will determine subsequent growth in these children.


J. Sanchez: None. J. Hamilton: Advisory Panel; Novo Nordisk Canada Inc. Research Support; Mead Johnson & Company, LLC. G. Tomlinson: None. E. Asztalos: None. K. Murphy: None. B. Zinman: Advisory Panel; Abbott Diabetes, Boehringer Ingelheim International GmbH, Eli Lilly and Company, Merck & Co., Inc., Novo Nordisk Canada Inc., Sanofi K.K. D. Simmons: Research Support; Abbott, Hitachi, Ltd., Novo Nordisk. Speaker's Bureau; Sanofi. Other Relationship; Elsevier. A. Haqq: None. I.G. Fantus: None. A. Armson: None. J.F.R. Barrett: None. L.E. Donovan: Other Relationship; Dexcom, Inc., Inner Analytics, Medtronic, Tandem Diabetes Care, Inc. P. Karanicolas: Research Support; Baxter. Y. Jiang: None. S. Tobin: None. K. Mangoff: None. G. Klein: None. D. Feig: Advisory Panel; Novo Nordisk. Research Support; Apotex.


Canadian Institutes of Health Research

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