Gestational diabetes and its effect on fetal thymus size: a case-control study.

Abstract

Introduction: Fetal thymus size has recently been recognized as a sensitive parameter linked to pregnancy complications. This study investigates whether maternal diabetes affects fetal thymus size, potentially offering a means to identify at-risk fetuses before birth.

Methods: This study was designed as a case-control study conducted from September 2023 to November 2024 in Iran. The study samples included 112 diabetic women (gestational diabetes or pre-pregnancy diabetes) as the case group and 112 healthy pregnant women attending the same hospital as the control group. Data were collected using a researcher-designed demographic questionnaire, and fetal thymus size was measured via abdominal ultrasound. Fetal thymus size is calculated using the thymic-thoracic ratio (TTR) and the thymus circumference.

Results: A statistically significant difference was observed between the two groups regarding body mass index (BMI), an obstetric and demographic variable. The thymic-thoracic ratio (TTR) and the thymus circumference in diabetic pregnancies were statistically significantly lower than in the control group (p = 0.000). Odds ratios (95% CI) for the TTR index were 0.61 (CI 95%: 0.48 to 0.78), and thymus circumference was 0.95 (CI 95%: 0.93 to 0.97).

Conclusion: The present study indicated that a reduction in fetal thymus size may be associated with diabetes in pregnant women. However, it remains to be determined whether ultrasound evaluation of fetal thymus size can help predict perinatal outcomes in diabetic women.