Genetic problems, indiscriminate drug use, infection and viral fever during early stages of pregnancy are contributing to a steady rise in congenital heart disease (CHD) among children in Calcutta, at a time when it is on the decline in most developed nations.

Faced with the uphill task of preventing the incidence of CHD from shooting up further, about 300 paediatricians and cardiologists will come together on Sunday to discuss ways to implement immediate pre-natal techniques to effectively cut down congenital defects.

At present, 0.6 to 0.8 per cent of the newborns suffer from CHD in the metros, including Calcutta. The figure is between 0.8 and one in most advanced countries.

?It?s high time for us to take action. That?s why we have decided to organise the brainstorming session. The aim is to arrive at a consensus on the introduction of pre-natal diagnostic facilities in city hospitals,? said cardiac surgeon Ajay Kaul, of the BM Birla Heart Research Centre, the venue for the interaction session.

In India, about 112,000 children are born with birth anomalies every year, of whom about 50,000 require immediate surgery. Unfortunately, only 2,000 to 2,500 babies are operated upon.

?While a lot of cases are not reported, there are others whose parents cannot afford treatment. But we can prevent CHD by emphasising more on early diagnosis through methods like intra-uterine echocardiography,? said Kaul.

Experts say that three broad categories of CHD are difficult to treat. The first comprises cases where pure blood is shunted from the left to the right side of the heart.

?This is known as a hole in the heart,? explained Moushumi Sehgal, paediatric cardiac intensivist at Rabindranath Tagore International Institute of Cardiac Sciences.

Obstruction of blood flow to the heart and under-developed ventricles among children comprise the other categories.

?Congenital heart defects create an immeasurable public health burden in the form of foetal loss, infant mortality, social costs and disability,? Sehgal said.