Evaluation of prenatal changes in fetal cardiac morphology and function in maternal diabetes mellitus using a novel fetal speckle-tracking analysis: a prospective cohort study.

Background: Due to metabolic changes in the second trimester and the increasing number of pregnant women with obesity and advanced maternal age, the incidence of gestational diabetes mellitus (GDM) remains high. This study aimed to evaluate the effects of GDM on fetal cardiac morphology and function, and to determine whether these changes increase with increasing estimated fetal weight (EFW).

Methods: Fifty-eight women with GDM (GDM group) and 58 women with a healthy pregnancy (control group) were included in this prospective observational cohort study. Each group included subgroups of 31 pregnant women with a gestational age between 24⁺⁰ weeks and 27⁺⁶ weeks as well as 27 pregnant women with a gestational age between 28⁺⁰ weeks and 40⁺⁰ weeks. For all fetuses, a cine of 2-3 s in the four-chamber view was obtained, and online speckle-tracking analysis was performed using the GE Automatic Fetal Heart Assessment Tool (fetal HQ; General Electric Healthcare Ultrasound, Zipf, Austria) to measure the global sphericity index (GSI), global longitudinal strain (GLS), fractional area change (FAC), 24-segment sphericity index (SI), and 24-segment end-diastolic diameter of the left ventricle (LV) and right ventricle (RV). Data were analyzed using the independent t-test and Wilcoxon rank-sum test, as applicable.

Results: The GDM group (mean HbA1c value was 5.3 ± 0.57 mmol/L) showed a lower GSI value than the control group (1.21 vs. 1.27, P = 0.000), which indicated a rounder shape of the heart. In addition, fetuses in the GDM group demonstrated significant impairment in cardiac function compared to those in the control group (LV-GLS: -18.26% vs. -22.70%, RV-GLS: -18.52% vs. -22.74%, LV-FAC: 35.30% vs. 42.36%, RV-FAC: 30.89% vs. 36.80%; P = 0.000 for all). Subgroup analyses according to gestational age (24⁺⁰-27⁺⁶ weeks and 28⁺⁰-40⁺⁰ weeks) showed that the statistical differences were retained between the GDM and control groups in each subgroup.

Conclusions: Fetuses of women with GDM present with signs of biventricular systolic dysfunction according to deformation analysis using fetal HQ. Additionally, the heart had a rounder shape in the GDM group than in the control group. This study showed that fetal HQ can be used to assess fetal cardiac morphology and function easily and quickly, and the effects of GDM on fetal cardiac morphology and function appeared from the second trimester. Thus, whether earlier and stricter clinical intervention was necessary remained to be further studied. Furthermore, future studies will need to supplement the effects of blood glucose levels on GLS, FAC, GSI, and 24-segment SI. Additionally, the long-term follow-up after birth should also be improved to observe the influence of changes in the indicators on the prognosis.