Cardiac and Vascular Adaptation During Pregnancy in Asian and Caucasian Women: Insights from a Prospective Cohort Study

<b>Background/Objectives:</b> Ethnicity is associated with differences in cardiac structure and function in non-pregnant populations, but pregnancy-specific data-particularly for myocardial deformation-remain limited. We investigated whether ethnicity influences cardiac geometry, biventricular and biatrial mechanics, hemodynamics, and carotid vascular indices in healthy women during the third trimester of pregnancy. <b>Methods:</b> In this prospective, monocentric study, 80 healthy women with singleton third-trimester pregnancies were enrolled, including 40 Asian and 40 Caucasian women matched for age and body mass index. All participants underwent standardized clinical and laboratory evaluation, comprehensive transthoracic echocardiography with Doppler, speckle-tracking analysis of both ventricles and atria, and bilateral carotid ultrasonography. Logistic regression analyses were performed in Asian women to identify correlates of supranormal left ventricular ejection fraction (LVEF ≥ 70%) and enhanced left ventricular global longitudinal strain (LV-GLS > 20%). <b>Results:</b> Age and gestational age were similar between groups, whereas body surface area was lower in Asian women (1.65 ± 0.12 vs. 1.77 ± 0.15 m², <i>p</i> < 0.001). Asian women exhibited smaller left ventricular dimensions and volumes but higher LVEF (median 71.6% vs. 66.4%, <i>p</i> < 0.001). Heart rate and blood pressure were comparable, whereas stroke volume [45.5 ± 9.6 vs. 68.0 (48.9-110) mL, <i>p</i> < 0.001] and cardiac output (3.9 ± 0.9 vs. 4.9 ± 0.8 L/min, <i>p</i> < 0.001) were lower in Asian women, who also demonstrated higher total peripheral resistance and lower ventricular-arterial coupling (0.31 ± 0.09 vs. 0.37 ± 0.07, <i>p</i> = 0.001). Speckle-tracking echocardiography revealed higher LV-GLS (21.9 ± 1.9% vs. 20.5 ± 2.0%, <i>p</i> = 0.002), higher LV global circumferential strain, enhanced right ventricular longitudinal strain, and higher reservoir strain of both atria in Asian women. Carotid ultrasonography showed smaller common carotid diameter and cross-sectional area in Asian women (10.7 ± 2.5 vs. 13.7 ± 2.3 mm², <i>p</i> < 0.001). In regression analyses, supranormal LVEF was independently associated with smaller LV end-diastolic diameter (OR 0.39, 95% CI 0.16-0.97), while enhanced LV-GLS was independently associated with lower neutrophil-to-lymphocyte ratio (OR 0.04, 95% CI 0.00-0.87). <b>Conclusions:</b> Ethnicity is associated with multidimensional differences in cardiac geometry, myocardial mechanics, vascular load, and carotid structure in healthy third-trimester pregnancy. Ethnicity-aware interpretation and tailored reference ranges may improve the accuracy of echocardiographic assessment during late gestation.