Shearwave elastography (SWE) to detect hyperglycaemic changes in the placenta (a pilot feasibility study)

The placenta experiences histopathological changes under influence from diabetes. In-vivo placental stiffness scores quantifying these changes remains experimental.

In consecutive, consenting women attending high-risk diabetes in pregnancy clinics: two-dimensional shear-wave elastography (2D-SWE) was used to measure placental stiffness. Grayscale imaging alongside in-built ElastQ software enabled ten measurements/participant from the placental parenchymal bed recorded in kilopascals (kPa). Correlation between HbA1c and stiffness (kPa) was assessed by mixed-effects model for repeated measures. Secondary regression analysis examined differences between three subgroups. Type 1 and/or Type 2 Diabetes (T1DM, T2DM) were categorized on clinical grounds and gestational (GDM) based on International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria.

Among 27 participants, T1DM = 7 (mean HbA1c 7.1 ± 1.0%), T2DM = 5 (mean HbA1c 6.8 ± 1.1%), GDM = 7 (mean HbA1c 5.4 ± 0.3%) and controls without diabetes = 8 (mean HbA1c 4.9 ± 0.5%): mean age was 31 ± 4 years, mean gestational age at scanning 31 ± 5 weeks, mean BMI 31.1 ± 6.7 kg/m². Mean placental stiffness score was not significantly different (p > 0.05) between groups: T1DM 5.08 ± 0.30 kPa, T2DM 5.27 ± 0.46 kPa, GDM 5.26 ± 0.42 kPa, controls 5.84 ± 1.86 kPa. Placental stiffness and HbA1c were not correlated (p > 0.05). Placental stiffness measurements showed intra-individual co-efficient of variation ranging from 7.9% to 52.3% (latter occurring in the most technically difficult studies due to body habitus and/or anatomical positioning of placenta).

In this pilot study, 2D-SWE did not establish correlations between HbA1c and placental stiffness. Placental stiffness was not significantly increased with any diabetes subtype compared to controls. New or novel markers of placental stiffness and function are needed to identify deleterious effects of hyperglycaemia.