Gestational diabetes mellitus (GDM) is a metabolic condition characterized by glucose intolerance that begins or is first recognized during pregnancy [1]. The prevalence of GDM has increased worldwide because of changes in lifestyle, increasing maternal age, and rising obesity rates. Several maternal and fetal complications are associated with GDM, including preeclampsia, macrosomia, and an increased future risk of type 2 diabetes mellitus [2, 3].

GDM may be associated with transient microvascular alterations, although the risk and clinical significance of retinal involvement in isolated GDM remain less clearly defined than in pre-existing diabetes mellitus. The retina, being a highly vascular and metabolically active tissue, may reflect systemic microvascular changes associated with hyperglycemia. Microaneurysms, retinal hemorrhages, venous dilatation, and arteriolar narrowing are examples of retinal vascular changes that may serve as markers of underlying microangiopathy [4, 5].

Fundus imaging is a non-invasive and reliable method for visualization of the retinal vasculature and documentation of subtle vascular changes. Advances in imaging technology have improved the ability to detect retinal abnormalities at an early stage, allowing timely documentation and follow-up. Although diabetic retinopathy has been extensively studied in chronic diabetes mellitus, data regarding retinal vascular findings specifically associated with GDM are comparatively limited [6-8].

Early detection of retinal vascular changes in patients with GDM may provide useful information about microvascular involvement and metabolic control. However, GDM should be differentiated from pre-existing diabetes, in which pregnancy-related progression of diabetic retinopathy is well recognized and retinal screening is clearly recommended [9].

The purpose of this study was to evaluate retinal vascular changes in pregnant women with GDM using fundus imaging and to assess their association with treatment modality [10, 11].

This prospective observational study was conducted at SBMCH & RI from July 2024 to February 2025 in collaboration between the Departments of Obstetrics and Gynaecology and Ophthalmology. A total of 25 pregnant women diagnosed with GDM were included. Ethical approval was obtained from the Institutional Ethics Committee prior to commencement of the study. Written and informed consent was obtained from all participants. Procedure: All participants underwent comprehensive clinical and obstetric assessment. The diagnosis of GDM was made using standard oral glucose tolerance test (OGTT) criteria. Following diagnosis, participants were referred for ocular evaluation. Fundus photography was performed using a non-mydriatic fundus camera under standardized settings. Retinal findings such as microaneurysms, retinal hemorrhages, venous dilatation, arteriolar narrowing, and other vascular abnormalities were evaluated and recorded. Retinal vascular changes were categorized as absent, mild, moderate, or severe based on fundus findings. Mild and moderate grades were assigned descriptively based on the number and extent of vascular findings, including venous dilatation, microaneurysms, and retinal hemorrhages. Severe changes were defined as sight-threatening retinal involvement such as severe non-proliferative diabetic retinopathy, proliferative diabetic retinopathy, or diabetic macular edema. Data Collection: Clinical data including age, gestational age, fasting and postprandial glucose levels, and treatment modality such as dietary management or insulin therapy were documented. Fundus photographs were evaluated and findings were recorded. The presence and severity of retinal vascular changes were analyzed in relation to treatment modality. Inclusion Criteria: • Pregnant women diagnosed with GDM. • Patients willing to undergo fundus examination and participate in the study. • Patients in any trimester of pregnancy. Exclusion Criteria: • Patients with pre-existing diabetes mellitus prior to pregnancy. • Patients with known retinal diseases unrelated to diabetes. • Patients with pre-existing hypertension or pregnancy-induced hypertension. • Patients unwilling to participate in the study. Statistical Analysis: Data were entered and analyzed using appropriate statistical software. Descriptive statistics were used to summarize demographic and clinical variables. The association between retinal vascular changes and treatment modality was analyzed using the Chi-square test or Fisher’s exact test, as applicable. A p-value of less than 0.05 was considered statistically significant.

A total of 25 pregnant women diagnosed with GDM were evaluated for retinal vascular changes using fundus imaging.

Table 1: Age Distribution of Patients

In this study, most patients were in the 26-30 years age group, followed by the 31-35 years age group.

Table 2: Gestational Age Distribution

In this study, most patients were evaluated during the second and third trimesters.

Table 3: Treatment Modality

In this study, 14 patients, or 56%, were managed with dietary measures, while 11 patients, or 44%, required insulin therapy.

Table 4: Retinal Findings on Fundus Examination

Note: Retinal findings are not mutually exclusive; some patients may have had more than one retinal finding.

No retinal abnormality was detected in 16 patients, or 64%. Among the retinal findings, venous dilatation was observed in 5 patients, microaneurysms in 3 patients, and retinal hemorrhages in 2 patients.

Table 5: Association between Treatment Modality and Retinal Changes

Retinal changes were observed in 6 of 11 insulin-treated patients and 3 of 14 diet-controlled patients. Although retinal changes were more frequent in the insulin-treated group, the association between treatment modality and retinal changes was not statistically significant in this small sample (Fisher’s exact test, p approximately 0.115).

Table 6: Grading of Retinal Vascular Changes

No retinal changes were observed in 16 patients, or 64%. Mild retinal vascular changes were observed in 7 patients, or 28%, and moderate retinal vascular changes were observed in 2 patients, or 8%. No severe or sight-threatening retinal involvement was observed in this study.

This study evaluated retinal vascular findings in pregnant women with GDM using fundus imaging. The retina provides a non-invasive window for assessing microvascular changes, although retinal involvement in isolated GDM remains less clearly established than in pre-existing diabetes. In the present study, a higher proportion of patients were evaluated during the second and third trimesters, and most patients were in the 26-30 years age group. No retinal abnormalities were detected in 64% of patients, while mild to moderate retinal vascular changes were observed in 36% of participants. Previous studies have reported that some women with GDM may show early retinal vascular changes, even without clinically evident diabetic retinopathy. In this study, venous dilatation was the most common retinal finding, followed by microaneurysms and retinal hemorrhages. These findings may represent early microvascular involvement associated with hyperglycemia in GDM [15-17]. Metabolic regulation may be important, as retinal changes were more frequently observed in insulin-treated patients in this study. Retinal changes were present in 6 of 11 insulin-treated patients compared with 3 of 14 diet-controlled patients. However, this association was not statistically significant, likely because of the small sample size. Previous research suggests that poor glycemic control is associated with microvascular complications, and larger studies are required to clarify this relationship in GDM [18, 19]. The majority of retinal changes observed in this study were mild, and no severe or sight-threatening retinal involvement was found. This may be related to the relatively short duration of hyperglycemia in GDM compared with chronic diabetes mellitus. Previous studies have also shown that pregnancy may influence the progression of diabetic retinopathy in women with pre-existing diabetes [12-14]. Current ophthalmic recommendations emphasize retinal assessment during pregnancy for women with pre-existing diabetes, whereas routine screening for isolated GDM is less clearly mandated and should be individualized based on clinical risk factors [20, 27, 28]. The present study has a few limitations. The findings may not be generalizable because of the small sample size, short follow-up period, and absence of a non-GDM control group. In addition, variations in fundus image interpretation may influence the evaluation of subtle retinal vascular changes [21-23]. Despite these limitations, this study suggests that fundus imaging may have clinical value in selected high-risk women with GDM. Fundus imaging is a simple and non-invasive method that may help detect retinal vascular changes in selected patients. Further research with larger sample sizes and longitudinal follow-up is needed to better understand the progression and clinical relevance of retinal vascular changes in GDM [24-26].

This study showed that fundus imaging detected mild-to-moderate retinal vascular changes in a subset of pregnant women with GDM. Venous dilatation, microaneurysms, and retinal hemorrhages were observed, while severe or sight-threatening retinal involvement was not seen. Retinal changes were more frequent among insulin-treated patients, although this association was not statistically significant in the present small sample. Fundus imaging may be considered in selected high-risk GDM patients, particularly those with poor glycemic control, visual symptoms, or suspected pre-existing diabetes. Larger controlled longitudinal studies are required to clarify the clinical significance and long-term implications of retinal vascular changes in GDM.

Funding

None

Conflict of Interest:

None

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