AUTHOR=Bashir Mohammed , Khan Adeel , Ata Fateen , Abdel-Rahman Manar E. , Eltaher Faten , Desoye Gernot , Konje Justin C. , Abou-Samra Abdul-Badi 

TITLE=Differential Effects of First and Third Trimester HbA1c Levels on Neonatal Weight and Placental Mediation in Type 1 Diabetes

JOURNAL=Frontiers in Endocrinology

VOLUME=Volume 16 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2025.1595584

DOI=10.3389/fendo.2025.1595584

ISSN=1664-2392

ABSTRACT=ContextIn women with type 1 diabetes (T1D), the effects of glycaemic control on neonatal weight and the role of the placenta are not fully understood.ObjectiveThis study explores the relationship between glycaemic control, neonatal weight, and placental weight.DesignA retrospective observational longitudinal study of pregnant women with T1DM.SettingThe study included 265 women with T1D. The target for the first A1c was set at ≤ 7.0%, while the target for the last A1c was ≤ 6.5%. The cohort was divided into four groups based on whether they achieved their target A1c (T) or had levels higher than the target (H) at each end. These groups were classified as Target-Target (T-T), Target-High (T-H), High-Target (H-T), and High-High (H-H). For the secondary objective, we included 154 women for whom placental weight data were available.Main outcomeWe assessed the association between firstA1c, lastA1c, and neonatal weight, examining the mediation effect of the placenta.ResultsThe mean age of the participants was 29.4 years (SD 4.6), and the mean T1DM duration was 14.1 years (SD 7.1). The median neonatal weight was highest in the T-H group (3.56 kg) and lowest in the H-T group (3.20 kg) (p=0.009). FirstA1c was negatively correlated with neonatal weight (β-coefficient -150.9, p < 0.01), whereas lastA1c positively correlated (β-coefficient 162.5, p < 0.01). The association with firstA1c disappeared when correcting for placental weight, while lastA1c remained significant. The placenta mediates 65% of the impact of firstA1c on neonatal weightConclusionsPoor glycaemic control early in pregnancy is linked to lower neonatal birth weight, while poor control in the third trimester is associated with higher birth weight. These findings emphasize the importance of maintaining adequate glycaemic control before and during early pregnancy for better health outcomes.