(Photo/People.cn)

On Sept. 21, Chinese doctors in southern China’s Guangdong province carried out an operation on a 28-week-old fetus in order to fix a cardiac developmental defect of the unborn baby.

Using a miniature needle, a tiny balloon and a catheter, the doctors successfully operated on the unborn infant's heart - which was about the size of a walnut.

The surgery, done by Guangdong General Hospital, is the first heart operation performed on a fetus in China.

The mother, surnamed Xie, was told that one valve of the fetal heart was developing to be too narrow - a condition known as severe pulmonary stenosis. This meant that the amount of blood coming from the heart to the lungs was severely restricted.

Without surgery, the child would likely have been born with two ventricles evolving into one, a life-threatening condition that couldn't be fully repaired even after surgery.

Instead, a team of specialists carried out a nerve-wracking 20-minute operation on Sept. 21. They slowly inserted a tiny needle into the exact point of the narrow pulmonary valve, where a catheter was then installed to expand the valve. A tiny balloon attached to the catheter was passed along the wire and inflated, stretching the narrow valve.

Four days after the operation, doctors said the fetus had increased blood flow in the cured pulmonary valve, a sign of a successful operation. This means that the baby's right ventricle has a chance of recovering good function. They said a healthy baby is expected to be discharged in three months.

The mother is also recovering well after the procedure.