Maternal Pre-Pregnancy Glycemic Status and Developmental Outcomes in Korean Children Aged 18–36 Months: A Nationwide Population-Based Cohort Study (2014–2021)

Purpose: Maternal metabolic health is increasingly recognized as a critical factor influencing early childhood development. This study examined the relationship between maternal pre-pregnancy glycemic status and neurodevelopmental outcomes in early childhood using a large national cohort in Korea. Patients and Methods: We conducted a population-based retrospective cohort study using national health examination and Korean Developmental Screening Test data from 2014 to 2021. Maternal fasting plasma glucose levels measured within one year prior to conception through delivery were used to classify women into normal, prediabetes, and diabetes mellitus (DM) groups. Neurodevelopmental outcomes were assessed at 18-24 and 30-36 months across six domains: gross motor, fine motor, cognition, language, sociality, and self-care. Inverse probability of treatment weighting was applied to adjust for baseline differences and weighted relative risks (RRs) and 95% confidence intervals (CIs) were estimated. Results: Among 258,367 mother-child dyads, both prediabetes and DM were associated with significantly increased risks of developmental delays in multiple domains. Offspring of mothers with DM exhibited significantly increased risks of developmental delay across all domains at both 18-24 and 30-36 months, with the highest risk observed for self-care at 30-36 months (RR 1.466, 95% CI 1.408-1.525). Children of mothers with prediabetes also demonstrated increased risks in cognition (RR 1.061, 95% CI 1.008-1.117) and self-care (RR 1.119, 95% CI 1.058-1.184) at 18-24 months. Additionally, statistically significant elevations were observed in gross motor (RR 1.101, 95% CI 1.037-1.169), language (RR 1.058, 95% CI 1.019-1.100), and sociality (RR 1.106, 95% CI 1.060-1.154) skills at 30-36 months. Conclusion: Maternal pre-pregnancy glycemic abnormalities, even at the prediabetic level, were associated with an increased risk of developmental delays in early childhood. Optimizing maternal glycemic control prior to conception may promote more favorable developmental outcomes in offspring.