Comparison of Doppler Flow Parameters of Foetal Middle Cerebral Artery in Pregnancy with Gestational Diabetes versus Normal Pregnancy: A Cohort Study

Abstract

Introduction: Gestational Diabetes Mellitus (GDM) affects maternal placental blood flow. As a compensatory mechanism for placental haemodynamic changes, blood flow is redistributed from peripheral vessels to the brain. This re-distribution can be evaluated using doppler Ultrasonography (USG) measurements of the umbilical arteries and foetal middle cerebral arteries. Aim: To compare doppler flow parameters {Pulsatility Index (PI), Resistance Index (RI), Peak Systolic Velocity (PSV), Systolic-To-Diastolic (S/D)} of the foetal Middle Cerebral Artery (MCA) in pregnancy with gestational diabetes versus normal pregnancy, and to compare pregnancy outcomes in GDM versus non-GDM women. Materials and Methods: A prospective cohort study was conducted from November 2019 to November 2021 at the Department of Obstetrics and Gynaecology, Department of Radiology, and Department of Paediatrics in Tertiary care centre of New Delhi, India. All pregnant women attending the Antenatal Care Outpatient Department (ANC OPD) upto 34 weeks with an Oral Glucose Tolerance Test (OGTT) ≥140 mg/dL were defined as cases, and those with OGTT <140 mg/dL were taken as controls. All patients underwent doppler USG after 34 completed weeks, and doppler flow parameters (PI, RI, PSV, S/D ratio) were noted. Patient outcomes were recorded, including maternal outcomes such as mode of delivery, pregnancy-induced hypertension, polyhydramnios, stillbirth, and Intrauterine Death (IUD). Foetal outcomes such as APGAR (Activity Pulse Grimace Appearance Respiration) score, hypoglycemia, hyperbilirubinemia, admission to the Neonatal Intensive Care Unit (NICU), Respiratory Distress Syndrome (RDS), and neonatal death were also documented. Appropriate statistical tests were used for the statistical analysis (Chi-square test, Fisher’s exact test and Wilcoxon-Mann-Whitney test). Results: The mean age of GDM and non-GDM women was 27.40±3.57 years and 26.20±3.29 years, respectively. Among GDM women, 14 patients (31.1%) were primigravida, while there were 15 patients (33.3%) who were primigravida among non-GDM women. MCA PI was significantly higher in cases (1.79±0.36) compared to controls (1.65±0.19) (p-value=0.023), whereas MCA PSV was significantly lower in cases (45.86±2.17) than in controls (50.10±1.62) (p-value=0.001). Pregnancy-induced hypertension was observed in 28.9% of GDM women and 6.7% of non-GDM women, with the difference being statistically significant (p-value=0.006). There was a statistically significant difference between APGAR scores at 1 minute (p-value=0.030). However, there was no statistically significant difference in the APGAR scores at 5 minutes (p-value=0.242). Conclusion: Foetal MCA PI on doppler velocimetry was significantly higher in the GDM group, and MCA PSV was significantly lower in the study group, while MCA RI and MCA S/D ratio were not significantly different. Maternal complications were more common in GDM compared to non-GDM.

Keywords

• blood flow
• pregnancy-induced hypertension
• pulsatility index
• resistance index