At the end of the 4th week of gestation, the heartbeats of the embryo begin. The heart, whose development starts at the 3rd week of gestation, has rapid and ir

At the end of the 4th week of gestation, the heartbeats of the embryo begin. The heart, whose development starts at the 3rd week of gestation, has rapid and irregular contractions capable of pumping the blood inside the vessels. At this period, the developing circulatory system allows maternal- embryonic nutritive and gaseous changes at the chorionic villi. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3279166/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3279166/ May not be 'blood' but it's a heart; doing the function of a heart. It's life.