A now-standard treatment for premature babies, first proven over 30 years ago in a breakthrough Auckland trial, has been shown not to increase heart attack risks decades later.
There had been fears that the children of women given the steroid injections when at risk of giving birth prematurely might have
an increased chance of heart disease.
Researchers from Auckland University tracked down more than half of the nearly 1000 people born in the National Women's Hospital trial.
The expectant mothers were given injections of a steroid - betamethasone - or a placebo.
By speeding up fetal development, especially in the lungs, the medicine slashes the risk of health problems such as lung disease and bleeding into the brain in the premature babies. Lung disease is the main killer of premature babies.
The 30-year check-up found no differences between the placebo and treated groups' risk factors for heart disease and stroke. The only difference was that, in the steroid group, indicators of possible mild insulin resistance appeared.
Insulin resistance can be a pre-cursor of type 2 diabetes.
This finding "provides the first proof in humans that exposure to steroids before birth might permanently alter metabolism", said lead researcher Dr Stuart Dalziel.
The study, published in the British Lancet medical journal, was carried out because some scientists suggest that excess in-utero exposure to a substance like the steroid, which occurs naturally in the body, may be a cause of illnesses, including heart disease, in adulthood.
Professor Jane Harding, deputy director of the university's Liggins Institute and one of the researchers, said the benefits of the steroid treatment vastly outweighed any possible disadvantages.
"We know this is a very effective, safe treatment and we now know it's safe up to 30 years."
