Pregnancy and Neonatal Outcomes in Maturity-Onset Diabetes of the Young: A Systematic Review.

Maturity-onset diabetes of the young (MODY)-a monogenic form of diabetes-accounts for approximately 1-2% of all diabetes cases, with GCK-MODY being the second most commonly diagnosed type. Although the inherited nature of the disease implies that the interplay between maternal glycemia and fetal genotype directly influences neonatal outcomes, clinical guidelines for MODY-complicated pregnancies remain underdeveloped. A systematic literature search in the PubMed, Scopus, Web of Science, and Cochrane databases was conducted following the PRISMA guidelines. The study protocol has been logged in the PROSPERO registry with the identification number CRD42024609390. Data, such as MODY type, the gestational age at delivery, mode of delivery, insulin administration, mutational status of the fetus, fetal birthweight (FBW), occurrence of small-/large-for-gestational age fetus, shoulder dystocia, and neonatal hypoglycemia, were extracted and evaluated. Among 19 studies selected for the final analysis, 15 investigated perinatal outcomes in the GCK-MODY variant. Women diagnosed with GCK-MODY treated with insulin delivered approximately 1-2 weeks earlier than those managed with diet alone. FBW was significantly higher in GCK-negative as compared to GCK-positive offspring. Accordingly, fetal macrosomia was notably more common among unaffected neonates. In GCK-affected fetuses, insulin therapy was associated with a significantly lower FBW. Fetal genotype critically modifies perinatal outcomes in GCK-MODY pregnancies. In the absence of fetal genotyping, conservative management should be prioritized to mitigate the risks of fetal growth restriction and iatrogenic prematurity. As data regarding other types of MODY in pregnancy remain sparse, there is an urgent need for more research in this area.