Association Between HbA1c Levels and Postpartum Depressive Symptoms: Insights from Edinburgh Postnatal Depression Scale Screening After Gestational Diabetes Mellitus.

Background/Objectives: Depressive symptoms are more frequent following pregnancies complicated by gestational diabetes mellitus (GDM), prompting postpartum depression screening recommendations in the German S3 guideline. Although GDM is associated with increased postpartum depression risk, the relationships between postpartum metabolic parameters and the Edinburgh Postnatal Depression Scale (EPDS) scores remain unclear. We investigated whether metabolic markers measured during diabetes screening 6-12 weeks postpartum are associated with depressive symptoms. Methods: We retrospectively analyzed EPDS screenings conducted during postpartum testing at our inpatient clinic between 07/2021 and 02/2024. The EPDS is a validated 10-item tool (score range 0-30), with scores ≥10 indicating potential depression. Metabolic parameters included HbA1c, the 75 g oral glucose tolerance test (oGTT), insulin, and the Homeostasis Model Assessment index (HOMA index). Group comparisons were performed using non-parametric tests and receiver operating characteristic (ROC) analyses, with the Youden index identifying optimal cutoffs. Results: Among the 102 women presenting for postpartum testing, 43.1% had normal glucose tolerance, 54.9% prediabetes, and 2.0% diabetes. A total of 13.7% (n = 14) screened positive for potential depression, including two who reported suicidal ideations. Women with positive EPDS scores had significantly higher HbA1c [5.7% (38.3 mmol/mol) vs. 5.4% (35.5 mmol/mol), p = 0.013]. An HbA1c cutoff of 5.42% (35.75 mmol/mol) showed discriminatory ability for depressive symptoms with an Area Under the Curve (AUC) of 0.708 (CI 0.567-0.849). Other metabolic parameters showed no significant associations. Conclusions: Elevated postpartum HbA1c is associated with depressive symptoms after GDM pregnancies. An HbA1c threshold of 5.42% (35.75 mmol/mol) may help identify women at increased postpartum depression risk and prompt subsequent psychological assessment when depression screening is otherwise omitted.