Longitudinal assessment of maternal echocardiographic changes in singleton versus twin pregnancies and their association with preeclampsia risk

This study aimed to longitudinally assess maternal echocardiographic adaptations in singleton versus twin pregnancies and to evaluate their association with the development of preeclampsia (PE). We performed a prospective longitudinal cohort study involving 140 twin and 140 singleton pregnancies. Serial transthoracic echocardiography(TTE) examinations were conducted at four predefined gestational intervals: (1) 6–13+6 weeks, (2) 20–27+6 weeks, (3) 28–36+6 weeks, and (4) 6 weeks postpartum. Generalized linear mixed models (GLMMs) were employed to analyze longitudinal trends in cardiac function parameters. The cohort was categorized into four groups: normal singleton pregnancies (N = 112), PE singleton pregnancies (N = 15), normal twin pregnancies (N = 85), and PE twin pregnancies (N = 24). The study revealed that right heart morphology and systolic function showed similar trajectories across groups. However, twin pregnancies complicated by PE displayed an adaptive decline in hemodynamic adaptation starting from the second trimester, characterized by elevated total vascular resistance (TVR) and attenuated increases in cardiac output (CO) and stroke volume (SV) as pregnancy progressed. Additionally, twin pregnancies with PE showed significantly greater increases in interventricular septal thickness (IVST), left atrial anteroposterior diameter (LAAP), left atrial area (LAA), and left ventricular mass index (LVMI) compared to normal twin pregnancies. Moreover, left ventricular diastolic function was more impaired in twin pregnancies, with further deterioration in PE cases. Finally, we draw the conclusion that normal twin pregnancies exhibit more pronounced left heart morphological, diastolic, and hemodynamic changes compared to singletons, which are further exacerbated in PE cases. These findings underscore the heightened cardiovascular burden of twin gestation and its interaction with PE pathogenesis.