fetal heart developmentDespite the fact that the first human heart beat can be detected early in the first trimester, researchers from the University of Leeds report human heart tissues remain jumbled until walls develop late in pregnancy. The report was published in the Journal of the Royal Society Interface Focus.

When researchers from the University of Leeds set out to develop a working model of the fetal heart they stumbled on a large difference between human heart tissue and heart tissue development in other mammals. According to the study, human heart valves develop early in pregnancy – around the 8th week of gestation, but the muscles of the heart do not develop until much later – around the 20th week of gestation.

Previous heart studies have focused on animals or older/deceased humans. Animal hearts develop more quickly than human hearts and by the time the fetus is born, in most cases, the heart is fully developed so the actual musculature of the heart in early pregnancy has been relatively unstudied. In pigs, for example, pregnancy lasts just three months, so heart structures are fully developed within the first month of pregnancy. Though the heart beat can be detected around 22 days in humans, heart development takes longer. Researchers reported organized structures were noted in the second trimester.

Currently diagnostic technologies like MRI and X-rays are generally avoided during pregnancy so textbooks and medical literature is generally based on animal studies. Researchers believe a better understanding of how the human heart develops, particularly a timeline of development, could benefit fetal electrocardiology study and practice.

The Leeds research included scans from one mother starting in the 18th week of pregnancy through delivery. Additional studies with similar scans would prove extremely useful for the advancement of fetal heart research. Researchers are hoping to development structural models of the human heart from early pregnancy to birth using current and future fetal heart studies.

Source: University of Leeds