Placental virtual biopsy: 3D-US hemodynamics of normal pregnancy versus gestational diabetes

Abstract

Objectives: We used three-dimensional ultrasound with trans-abdominal Power-Doppler (3D-US PD) to determine placental vascular evolution in normal pregnancies (NP) and in insulin-dependent Gestational Diabetes Pregnancies (GDP). Study design: We obtained 473 measurements from 43 NP at 20 weeks -40 weeks gestation and 122 measurements from 70 insulin-dependent GDP at 22 weeks -40 weeks. Standardization was achieved recording three successive placental vascular tree volumes, measuring the spherical volume between the chorionic and basal plates always under or near funicular insertion. Parameters analysed were: mean intensity of blood flow (Flow Index, FI); percentage of volume occupied by vessels (Vascularisation Index, VI); and intensity of blood flow in the volume occupied by vessels (Vascularisation-flow index, VFI). Results: In NP, FI increased throughout early pregnancy and decreased before delivery and correlated with fetal parameters. In contrast, in GDP, FI was high from the onset, better correlated with placental parameters, and had a diagnostic cutoff value of 45, which was only found in 7% of NP at the end of the pregnancy. VI was variable and had a low diagnostic value, being related to placental parameters; VI values were significantly lower in NP ( 17.4 ± 7.4%) than in GDP (21 ± 12%) with a diagnostic cutoff point at 31%. In NP, FI-peak was at 32 weeks, two weeks after the VI-peak, while VFI showed no significant differences. Conclusions: The results showed that placental blood flow (FI) was related to fetal circulation, while the percentage of vessels per volume (VI) was related to maternal circulation. 3D-US PD indicated a diagnosis of GDP for FI > 45 and VI > 30%. We also discuss the values of change in VI that predict changes in fetal FI.