Sonographic Evaluation of Amniotic Fluid Index in Diabetic and Non-Diabetic Pregnancies During Second and Third Trimesters: A Comparative Cross-Sectional Study

Abstract

Background: Diabetes mellitus during pregnancy disrupts maternal–fetal metabolic balance and can significantly alter amniotic fluid dynamics. The Amniotic Fluid Index (AFI) serves as a critical sonographic marker of fetal well-being, yet regional evidence comparing AFI variations in diabetic and non-diabetic pregnancies remains limited. Understanding these differences is essential for refining antenatal monitoring and mitigating perinatal complications. Objective: To compare the Amniotic Fluid Index (AFI) and amniotic fluid echogenicity between diabetic and non-diabetic pregnant women during the second and third trimesters, and to determine whether maternal diabetes is associated with elevated AFI or altered fluid characteristics. Methods: A comparative cross-sectional study was conducted among 98 pregnant women (49 diabetic, 49 non-diabetic) attending tertiary care hospitals in Punjab, Pakistan. AFI was measured using the Phelan four-quadrant ultrasound technique, and echogenicity was qualitatively assessed as clear or increased. Data were analyzed using SPSS version 25.0, with independent t-tests and chi-square tests applied for group comparisons. Statistical significance was set at p < 0.05. Results: Diabetic pregnancies exhibited significantly higher AFI values than non-diabetic pregnancies in both trimesters—16.23 ± 2.47 cm vs. 14.97 ± 1.92 cm in the second (p = 0.021) and 13.67 ± 2.09 cm vs. 12.52 ± 1.66 cm in the third (p = 0.034). Polyhydramnios occurred more frequently among diabetic women (16.7% vs. 8.3% in the second trimester; 12.0% vs. 4.0% in the third), while increased echogenicity was more common in diabetic pregnancies (34.7% vs. 22.4%), though not statistically significant (p = 0.083). Conclusion: Maternal diabetes is significantly associated with elevated AFI across mid-to-late pregnancy, suggesting increased risk of polyhydramnios and related complications. Routine AFI monitoring in diabetic pregnancies is recommended to enhance fetal surveillance and improve perinatal outcomes.