More New Zealand families could benefit from a life-saving treatment for premature babies as new evidence from a major 10-year New Zealand and Australian trial confirms its long-term safety.
The treatment involves injecting pregnant women at risk of giving birth before 35 weeks’ with corticosteroids (different from muscle-building anabolic steroids). The steroids are synthetic versions of hormones normally released by the mother in late pregnancy. They flow through the placenta into the baby and speed up the development of her or his lungs, gut, cardiovascular and immune systems, which do not fully mature until after 36 weeks’.
Every year, around 5000 babies are born prematurely in New Zealand.
Babies whose mothers receive the steroids are less likely to die, less likely to have breathing problems and other serious health problems after birth, and any breathing problems tend to less severe, compared to babies whose mothers do not have the treatment.
A single course of the steroids halves the risk of the most common lung illness in premature babies, called respiratory distress syndrome, from 40 percent to 21 percent in babies born before 32 weeks’.
About twice as many babies will benefit from the treatment when mothers who remain at risk of an early birth receive a repeat dose after seven days. The problem is, while single courses are routinely given to at-risk women, not all are given repeat doses due to lingering and – it is now clear - misplaced doubts about the long-term safety of this powerful drug.
To check for long-term effects, researchers from Liggins Institute at the University of Auckland, and from the University of Adelaide, have tracked into mid-childhood the health and development of 1000 babies whose mothers either received repeat doses of steroids or a placebo. The 10-year trial was called the Australasian Collaborative Trial of Repeat Doses of Corticosteroids (ACTORDS).
The latest study out of the trial, published today in top journal Pediatrics, found no difference in the bone health (mass) of children at age six to eight in the treatment and placebo groups.
The main study from the mid-childhood follow-up was published in Pediatrics last October. It showed no adverse effects on brain development and general health. An earlier study found no adverse effects on cardiovascular and metabolic (gut) health.
As well as showing the immediate benefits of repeat doses to babies, studies from the ACTORDS trial have found no differences in the survival rates, health, development and body size of children whose mothers had received repeat steroids and those who had not.
“Taken together, these results should completely reassure doctors about the short term benefits and long-term safety of repeat doses – meaning they can use antenatal corticosteroids to their fullest benefit,” says Dr Chris McKinlay, a researcher at the Liggins Institute and neonatologist at Middlemore Hospital who was lead author on several of the papers.
“Concerns about the safety of repeat doses partly came from past animal studies that linked repeat doses with later adverse effects on the animal offspring,” he says.
“But ACTORDS is the largest clinical trial of humans in the world to date with school-age follow-up, and it has clearly shown children born to mothers who were given repeat corticosteroids were no more likely to have health or development problems than those born to women who weren’t given repeat doses.”