Association of mid-pregnancy ferritin levels with postpartum glucose metabolism in women with gestational diabetes.

Background: Ferritin, a key indicator of body iron levels, has been reported to associate with type 2 diabetes (T2DM) and the onset of Gestational diabetes mellitus (GDM). However, limited research explores the association between mid-pregnancy ferritin levels and the risk of postpartum abnormal glucose metabolism (AGM) in patients with GDM.

Methods: A retrospective cohort study was conducted in 1514 women with GDM recruited from January 2016 to January 2021, and 916 women were included. Demographic characteristics, medical history and family history, pregnancy complications were recorded. Multiple logistic regression models were performed to assess the association between mid-pregnancy ferritin levels and the risk of postpartum AGM.

Results: Following the postpartum oral glucose tolerance test, 307 (33.5%) exhibited AGM. The AGM group had higher mid-pregnancy serum ferritin levels [AGM vs NGT: 23 (11.7, 69) µg/L vs 17.80 (9.85, 40.7) µg/L, P < 0.001] and had a larger proportion of women with ferritin levels ≥30 µg/L (AGM vs NGT: 43.6% vs 31.4%, P < 0.001). Logistic regression analysis demonstrated that women with ferritin levels≥ 30 µg/L had a 1.566 times higher risk of developing postpartum AGM.

Conclusions: These findings indicate that elevated mid-pregnancy ferritin levels are significantly and independently associated with increased postpartum AGM risk in women with previous GDM. Consequently, cautious consideration is necessary for prescribing iron supplements in prenatal care, particularly for non-anemic women with GDM at high risk of developing diabetes after delivery.