Maternal cardiac changes in women with obesity and gestational diabetes mellitus

Background- Gestational diabetes mellitus (GDM) is the most prevalent metabolic disorder during pregnancy and is associated with increased risks of cardiovascular morbidity and mortality in later life. Compromised cardiac energy production is an important contributor to most forms of heart disease. The changes in myocardial energetics in GDM have not been characterized previously.

Objective- We investigated if women with GDM in the third trimester of pregnancy exhibit adverse cardiac alterations in myocardial energetics, function or tissue characteristics.

Methods- Thirty-eight healthy pregnant (HP) women and thirty women with GDM were recruited. Participants underwent phosphorus magnetic resonance spectroscopy and cardiovascular magnetic resonance for assessment of myocardial energetics (phosphocreatine to ATP ratio (PCr/ATP)), tissue characteristics, biventricular volumes and ejection fractions, left ventricular (LV) mass, global longitudinal shortening (GLS) and mitral in-flow E/A ratio.

Results- Participants were matched for age, gestational age and ethnicity. The women with GDM had higher body-mass index (27±4 versus 33±5kg/m2; p=0.0001), systolic (115±11 versus 121±13mmHg; p=0.04) and diastolic (72±7 versus 76±9mmHg; p=0.04) blood pressure. There was no difference in NTproBNP concentrations between the groups.

The women with GDM had lower myocardial PCr/ATP ratio (2.2±0.3 versus 1.9±0.4; p<0.0001), accompanied by lower LV end-diastolic volumes (76±12 versus 67±11mL/m2; p=0.002) and higher LV mass (90±13 versus 103±18g; p=0.001). While ventricular ejection fractions were similar, the GLS was reduced in women with GDM (-20±3 versus -18±3%; p=0.008).

Conclusions- Despite no prior diagnosis of diabetes, women with obesity and GDM manifest impaired myocardial contractility and higher LV mass, associated with reductions in myocardial energetics in late pregnancy compared to lean women with healthy pregnancy. These findings may aid our understanding of the long-term cardiovascular risks associated with GDM.