Placental dysfunction and adverse outcomes are associated with fall in insulin requirements in pregnant women with pre-existing diabetes: A retrospective study

Aim: To determine the association between the degree of falling insulin requirements and placental insufficiency related adverse outcomes in pregnancies of women with pre-existing diabetes. Method: A retrospective medical record review of all women with pre-existing diabetes on insulin who birthed at a regional hospital in Queensland, Australia over a 5-year period. Maternal characteristics and pregnancy outcomes were reported with different categories of falling insulin requirements, determined by third trimester insulin peak and trough daily doses. Results: Of 184 women 85% had type 2 diabetes. Fifty-nine (32%) women had a fall in insulin requirements (FIR): 19 (10.3%) had FIR < 15%, 13 (8.2%) had FIR 15-49.9% and 25 (13.6%) had FIR of ≥ 50%. Mothers affected by FIR had longer mean hospital length of stay (4.8 days vs 3.9 days, p < 0.01) and had higher rates of features of preeclampsia (proteinuria, hypertension, thrombocytopenia, abnormal liver function) compared with to those with no FIR. Across all degrees of falling insulin requirement, there was an association with severe pre-eclampsia, OR (95%CI) 3.9 (1.04–14.5), 7.3 (2.0-26.5), 9.7 (3.3–28.5) in groups FIR < 15%, 15–49%, ≥ 50% compared to no FIR respectively. There was an association between FIR and neonatal outcomes of APGAR < 7 at 5mins (40% vs 24%, p = 0.03) and respiratory distress (14% vs 5%, p = 0.02). Conclusion In women with pre-existing diabetes, any degree of fall in insulin requirement was associated with adverse maternal and neonatal outcomes related to placental dysfunction and should prompt urgent evaluation.