Sight-threatening diabetic retinopathy during and after pregnancy - a nationwide matched cohort study

Objective To evaluate the risk of treatment for sight-threatening diabetic retinopathy (DR) defined as panretinal photocoagulation for proliferative DR or anti-VEGF injections for diabetic macular edema (DME) during and after pregnancy compared to non-pregnant controls. Research Design and Methods A matched cohort study of women with type 1 diabetes, giving birth in 2013-2022 with DR-levels recorded in the national Danish Registry of Diabetic Retinopathy during and after pregnancy. Controls consisted of non-pregnant women with type 1 diabetes, individually matched by baseline DR-level. Data was collected from 36 months prior to pregnancy until 36 months after from relevant national registers. Results We included 1041 pregnant women and 1041 matched controls. At baseline, the median duration of diabetes was 13 (IQR 6-19) and 10 (5-17) years for cases and controls. Median baseline HbA1c was 57 (50-67) vs. 64 (55-79) mmol/mol (7.4 vs 8%), and DR was present in 42.7% vs. 42.7%. During and after pregnancy treatment of proliferative DR with panretinal photocoagulation occurred to a similar extent as in the controls (1.2% vs. 1.1%, (OR 1.18(95%Cl: 0.53;2.66)) and 2.7% vs. 2.9%, (OR 0.93(95%Cl: 0.55;1.57)) respectively). Treatment of DME was rare in both groups. Progression to proliferative DR, was not higher in the pregnant group (adjusted hazard ratio 0.64(95%Cl: 0.32;1.31)). Conclusions In this nationwide register study of women with type 1 diabetes, pregnant cases and retinopathy matched non-pregnant controls had a similar risk of developing sight-threatening DR, requiring treatment during and within 36 months after pregnancy.