Pregnancy and diabetic retinopathy

Abstract

Background: An increase in the worldwide prevalence of diabetes, especially among younger populations, has led to a higher prevalence of pre-existing diabetes among pregnant women. The precise mechanisms underlying the development or progression of diabetic retinopathy (DR) during pregnancy are not entirely understood. This narrative review incorporates all available data to offer fresh insights into the pathogenesis and mechanisms of the pregnancy-induced development and/or progression of DR. Moreover, the author aims to offer clinical recommendations for DR both before conception and during pregnancy to appropriately counsel these susceptible patients. Methods: A literature search was performed using various combinations of the following keywords: diabetes, pregnancy, diabetic retinopathy, ocular, eye, retina, microangiopathy, mechanism, pathophysiology, hyperglycemia, hypoxia, neovascularization, growth factors, immune system, blood flow, and recommendations. The search was conducted using PubMed/MEDLINE, ISI Web of Science, Scopus, and Google Scholar, and only English articles published from January 1, 2020, to December 31, 2023, involving human participants, were considered. The International Diabetes Federation Diabetes Atlas website was searched for clinical recommendations. Results: Pregnancy-induced hyperglycemia, blood flow changes, growth factors, and the immune system play important roles in the development and progression of DR. Hyperglycemia leads to significant stress on the capillary endothelium through increased glucose flux via the polyol and hexosamine pathways, activation of protein kinase C, and increased formation of advanced glycation end-products. These pathways act in several ways that may lead to increased oxidative stress, inflammation, and vascular blockage. Thus, eye examinations are crucial before, during, and up to 12 months after pregnancy. Individuals with severe non-proliferative and proliferative DR should gradually decrease their blood glucose levels to near-normal levels over a period of 6 months before conception. Statins and medications inhibiting the renin–angiotensin system should be discontinued before pregnancy or at the initial antenatal visit if they are still being used. Retinal examinations should be performed shortly after conception and during the first trimester using tropicamide eye drops and digital imaging. Subsequent examinations should be scheduled based on DR severity at the initial examination. Conclusions: While the precise mechanism underlying the progression of DR during pregnancy remains uncertain, the available literature suggests that pregnancy-induced hyperglycemia, blood flow changes, growth factors, and the immune system play important roles in its development and progression. Pregnant women with diabetic eye manifestations benefit from the expertise of multidisciplinary teams comprising ophthalmologists, diabetologists, and gynecologists to improve both maternal and perinatal outcomes. Moreover, postpartum follow-up requires special attention.