Fetal cardiac remodelling in pregnancies complicated by gestational diabetes mellitus: a prospective cohort study

Introduction
Pregnancies complicated by gestational diabetes mellitus (GDM) have a higher risk of fetal and neonatal cardiac remodelling. Our aim was to evaluate the sphericity index (SI), a variable reflecting the severity of cardiac shape changes, in fetuses of GDM mothers and correlate the quality of glycaemic control expressed by glycated haemoglobin (HbA_1c) levels.

Material and methods
This was a prospective cross-sectional study including 276 pregnancies complicated by GDM (185 with good control [HbA_1c ≤ 5.5] and 91with poor control [HbA_1c > 5.5]) and 140 uncomplicated gestations. All women underwent ultrasound biometric evaluation, Doppler and echocardiographic assessment, including evaluation of the SI at a median gestational age of 30 weeks. Comparisons among groups were performed.

Results
Compared to the control group, fetuses from GDM mothers showed a higher body mass index (p = 0.003), estimated fetal weight (p = 0.037), gestational age at delivery (p = 0.042), birthweight (p = 0.006), and birthweight centile (p = 0.012). There was no difference in maternal age, parity, gestational age at ultrasound, and maternal or fetal Dopplers. In pregnancies with GDM right ventricle SI (1.42 for good control and 1.33 for poor c control) the SIs were higher compared to control pregnancies (1.55; p = 0.001). No difference was found in left ventricle SI (1.51 for good and 1.59 for poor control) when compared to the control group (1.76; p = 0.08). When stratifying the analysis according to glycaemic control, right SI was lower in pregnancies with poor compared to good control (p = 0.002).

Conclusions
The risk of fetal cardiac remodelling is higher in pregnancies complicated by GDM, and it is independent of maternal and fetal Doppler. These changes occur at the level of the right ventricle and are influenced by glycaemic control.