Dr Janet Rowan - a diabetes specialist at National Women's Hospital in Auckland - was commenting after a conference was told by Waikato Clinical School specialist Professor David Simmons that there was "a tsunami of diabetes in this country".

"This epidemic is moving extremely fast. What's scary is what's happening to these babies," he told the conference. There has been a rise in the number of pregnant women with diabetes, increasing the risk of their babies also developing the disease.

One study showed children of mothers who had diabetes in pregnancy had about a three times higher risk of developing the disease than older siblings born before their mothers developed the disease.

Dr Rowan said this showed diabetes in pregnancy was a stronger force in passing on a predisposition to the disease than just inheriting genes for it from either parent.

She called this the "inter-generational amplification of diabetes".
Of the 70 per cent of the clinic's gestational diabetes patients who return for blood-glucose tests six weeks after birth, 10 per cent have type 2, 15-20 per cent have impaired glucose tolerance (a pre-diabetic condition) and in the rest, glucose levels return to normal.

The increase in diabetes in pregnancy is linked to the rise in the wider population, leading to more women of child-bearing age developing the disease. It is also linked to delayed child-bearing, because the diabetes rate rises with age.