A baby's first heartbeat happens as early as 16 days after conception, a new study has discovered.

Until now, researchers thought that the first time our heart muscle contracted to beat was at 8 days after conception in mice which equates to around day 21 of a human pregnancy.

Now, a team funded by the British Heart Foundation (BHF) at the University of Oxford have found it is far earlier.

In the study, published today in the scientific journal eLife, researchers studied the developing mouse heart and found that the muscle started to contract as soon as it formed the cardiac crescent – an early stage in heart development.

WHAT IT COULD MEAN Congenital heart disease is diagnosed in at least 1 in 180 births, which equates to around 4,000 each year or 12 babies each day, in the UK, and affecting nearly 40,000 births in the US. The researchers ultimately hope that by understanding more about how the heart forms in the womb they will one day be able to prevent heart conditions that arise as a foetus develops. Advertisement

'We are trying to better understand how the heart develops, and ultimately what causes the heart defects that develop in the womb before birth and to extrapolate to adult heart repair, said BHF Professor Paul Riley, who led the research at the University of Oxford.

'By finding out how the heart first starts to beat and how problems can arise in heart development, we are one step closer to being able to prevent heart conditions from arising during pregnancy.

'We also hope that this new research will help us to learn how the beating of new heart muscle cells might be triggered in replaced muscle after a heart attack.'

Professor Riley and his team also hope that these findings will bring them closer to being able to repair damaged muscle after a heart attack, which can lead to heart failure.

They have demonstrated earlier beating of the heart in mouse embryos which, if extrapolated to the human heart, suggests beating as early as 16 days after conception.

In the study, published today in the scientific journal eLife, researchers studied the developing mouse heart and found that the muscle started to contract as soon as it formed the cardiac crescent – an early stage in heart development.

In mice, this crescent forms 7.5 days after conception, which is equivalent to day 16 in the human embryo.

The researchers ultimately hope that by understanding more about how the heart forms in the womb they will one day be able to prevent heart conditions that arise as a foetus develops.

Previously, it was thought that the heart started to contract a stage later, when the heart appears as a linear tube.

Congenital heart disease is diagnosed in at least 1 in 180 births, which equates to around 4,000 each year or 12 babies each day, in the UK.

The researchers ultimately hope that by understanding more about how the heart forms in the womb they will one day be able to prevent heart conditions that arise as a foetus develops.

By adding fluorescent markers to calcium molecules within the mouse embryo, the team were able to see at exactly which point in time calcium signals, as the trigger telling our heart muscle cells to contract, become coordinated enough to produce a heartbeat.

Congenital heart disease is diagnosed in at least 1 in 180 births, which equates to around 4,000 each year or 12 babies each day, in the UK.

HOW THE HEART DEVELOPS The heart is the first organ to form during pregnancy and is critical in providing oxygen and nutrients to the developing embryo. The process of heart development is highly conserved between mammalian species, meaning that these findings may add considerably to our understanding of how the human heart develops. Advertisement

The team also found that this initiation of beating was essential for the heart to develop properly at an early stage and that a protein, called NCX1, plays a key role in the generation of the calcium signals needed to produce the beating action of the heart.

Professor Sir Nilesh Samani, Medical Director at the British Heart Foundation, which funded the research, said:

'This study describes some of the very first stages in the development of a beating heart, identifies some of the key molecules involved and shows that the initiation of the beat itself has a bearing on the further development of the heart.

'Such fundamental research is vital in understanding and ultimately preventing diseases that affect the heart.'

The BHF is a major UK funder of research into congenital heart disease with millions of pounds worth of research projects happening across the country, all made possible by donations and support from the public.