Risk factors for the development or progression of diabetic retinopathy in pregnancy: Meta-analysis and systematic review

Background Diabetic retinopathy (DR) is the leading cause of blindness in the working-age population, and it increases in severity during pregnancy. Methods Systematic review of literature from PubMed, Cochrane Library and Web of Science using keywords 'diabetic retinopathy' and 'pregnancy' and 'progression' from inception to 2021 was completed. Included studies were (1) peer-reviewed observational studies addressing progression/development of DR in pregnancy, (2) provided the number of diabetic patients that developed/progressed in DR during pregnancy, and (3) included differential data on variables between progression and non-progression groups. This was applied by two independent researchers and referred to a third researcher as necessary. Twenty-seven of the original 138 studies met this criterion. Data were pooled and analysed using fixed-effects in meta-analysis. Results From 27 studies, 2537 patients were included. Pre-eclampsia [Risk Ratio (RR) 2.62 (95% CI = 1.72, 4.00)] and hypertension treatment during pregnancy [RR 2.74 (95% CI = 1.72, 4.00)] were significantly associated with the development/progression of DR. HbA1c at baseline [MD 0.82 (95% CI = 0.59, 1.06)], duration of diabetes [mean difference (MD) 5.97 (95% CI = 5.38, 6.57)], and diastolic blood pressure at baseline [MD 3.29 (95% CI = 0.46, 6.12)] were all significantly higher in the progression group while only mean birth weight [MD -0.17 (95% CI = -0.31, -0.03)] was significantly higher in the non-progression group. Conclusions This study fills a gap in the literature and provide physicians with more information on the risk factors associated with the progression of DR in pregnancy and how to counsel this vulnerable patient population appropriately.