VEGFB and cardiac hypertrophy: Normal pregnancy in mice involves a marked increase in blood volume and cardiac output that is associated with the growth of heart size by day 18 postcoitum and reversion of cardiac hypertrophy by day 7 postdelivery.40 To know whether the expansion of VEGFB-iECs was triggered during endogenous physiological cardiac hypertrophy, we isolated cardiac ECs from αMHC-VEGF-B mice and WT littermates at day 18 of pregnancy and 7 days postdelivery and subjected them to scRNA-seq analysis.