Maternal myocardial alterations during pregnancy and their recovery twelve months' post-partum in women with pregnancies complicated by gestational diabetes or preeclampsia- a single centre, longitudinal cohort study

Background

Gestational diabetes mellitus (GDM) and preeclampsia (PE) are the leading obstetric complications of pregnancy. Both are associated with a substantial increase in the risk of long-term cardiovascular disease. However, pregnant women are underrepresented in clinical research and the mechanisms of long-term cardiovascular complications in women with obstetric complications remains to be elucidated.

Objectives

This longitudinal cohort study was designed to assess maternal cardiac alterations during the third trimester of pregnancy and their recovery twelve-months post-partum in women with GDM (n=30) or preeclampsia (n=22) compared to women with healthy pregnancies (HP)(n=38).

Methods

31P-MRS and CMR were used to define myocardial phosphocreatine to ATP ratio (PCr/ATP), tissue characteristics, left ventricular (LV) volumes, mass, ejection fraction (EF), global longitudinal shortening (GLS), and diastolic function (mitral in-flow E/A ratio). Investigations were repeated 12-months postpartum. With obesity as a major and common risk factor for both GDM and PE, 10 overweight and 10 normal-weight nulliparous women served as non-pregnant controls.

Results

Participants were matched for age and ethnicity. Both the GDM and PE groups had higher BMI compared to the HP. Compared to the HP group, women with GDM had higher LV mass (90[85,94] vs 103[96,112]g; p=0.001) and lower myocardial PCr/ATP (2.2[2.1,2.4] vs 1.9[1.7,2]; p<0.0001), LV end-diastolic volumes (EDV)(76[72,80] vs 67[63,71]ml, p=0.03) and GLS (20[18,21] vs 18[17,19]%; p=0.008). Compared to the HP group, at similar magnitudes to women with GDM, the women with PE exhibited higher LV mass (90[85,94] vs 118[111,125] g; p<0.0001) and lower myocardial PCr/ATP (2.2[2.1,2.4] vs 1.9[1.8,2.1]; p=0.0004) and GLS (20[18,21] vs 16[14,17] %; p=0.01). There were no significant differences in PCr/ATP, LV EDV, mass or GLS between the GDM and PE groups. Twelve-months postpartum there were no significant changes in any of the cardiac assessments in women in the HP, GDM or PE groups compared to their respective third-trimester pregnancy assessments (Figure-1). Compared to nulliparous normal-weight controls, HP was associated with no significant differences in myocardial PCR/ATP, LV volumes, mass, EF, diastolic function, or GLS. The overweight nulliparous controls showed significantly higher LV mass and lower myocardial PCr/ATP and GLS than normal-weight controls. There were no significant differences in LV mass, PCr/ATP or GLS between the overweight nulliparous controls and GDM or PE groups during or after pregnancy. Myocardial triglyceride content [% of water signal] in HP was 0.77 (0.39,1.2) % versus GDM 0.96 (0.4,1.5) % and PE 0.38 (0.3,1) %, p=0.3 indicating myocardial steatosis in the GDM cohort. The babies born to women in the HP group were on average of higher birth-weight compared to the GDM and preeclampsia groups (HP:3407(3261,3553) vs GDM:3003(2680,3325) vs Preeclampsia:3010(2785,3235) g; p=0.02). Placental mal-perfusion and infarction was detected in a higher percentage of women with GDM (59%) and preeclampsia (55%) than in HP (39%).

Conclusions

Despite distinct aetiologies women with GDM and PE exhibit a similar myocardial phenotype during and after pregnancy with persistent subtle abnormalities in myocardial PCr/ATP ratio, LV mass and GLS compared to women with HP during pregnancy and twelve months’ postpartum assessments. Women with GDM and PE show similar myocardial alterations to nulliparous women with obesity, suggesting that the myocardial changes are predominantly driven by obesity-associated metabolic dysfunction.

Conflict of Interest

None