Importance: Diabetic retinopathy (DR) may be worsened by pregnancy in pregnant women with preexisting type 1 diabetes (T1D) or type 2 diabetes (T2D). Conflicting findings from previous studies have resulted in inconsistencies in guidelines regarding DR management in pregnancy. Global estimates of DR prevalence and progression in pregnancy are therefore required to provide clearer information about the overall true burden of DR in this population.
Objective: To estimate the prevalence of DR and its progression rate in pregnant women with preexisting T1D or T2D diagnosed before pregnancy.
Data sources: For this systematic review and meta-analysis, conducted from November 27, 2018, to June 29, 2021, a systematic literature search was conducted in MEDLINE/Ovid, Embase/Ovid, and Scopus databases to identify English-language articles that were published from inception through October 2020.
Study selection: Observational studies that reported on DR and its changes in pregnant women with preexisting T1D and T2D.
Data extraction and synthesis: Two independent reviewers extracted relevant data from each included study. Data were pooled using a random-effects model with the Freeman-Tukey double arcsine transformation. This study followed the Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting guidelines.
Main outcomes and measures: Prevalence of any DR, proliferative DR (PDR), and DR progression rates.
Results: A total of 18 observational studies involving 1464 pregnant women with T1D and 262 pregnant women with T2D were included in the analysis. The pooled prevalence of any DR and PDR in early pregnancy was 52.3 (95% CI, 41.9-62.6) and 6.1 (95% CI, 3.1-9.8) per 100 pregnancies, respectively. The pooled progression rate per 100 pregnancies for new DR development was 15.0 (95% CI, 9.9-20.8), worsened nonproliferative DR was 31.0 (95% CI, 23.2-39.2), progression from nonproliferative DR to PDR was 6.3 (95% CI, 3.3-10.0), and worsened PDR was 37.0 (95% CI, 21.2-54.0). DR progression rates per 100 pregnancies were similar between the T1D and T2D groups, except for the development of new DR (T1D groups: 15.8; 95% CI, 10.5-21.9; T2D groups: 9.0; 95% CI, 4.9-14.8). A global trend toward a lower DR progression rate was observed after the 1989 St Vincent Declaration.
Conclusions and relevance: Results of this systematic review and meta-analysis suggest that women with T1D and T2D had a similar risk of DR progression during pregnancy. Despite improvements in the management of diabetes and diabetes during pregnancy, DR prevalence and progression in pregnant women with diabetes remains higher than the nonpregnant population with diabetes, highlighting the need to improve DR management in pregnancy.