A new joint New Zealand-Australian study is good news for parents whose babies were given steroids before birth to prevent serious complications of premature delivery.
Antenatal steroids have been used to mature baby's organ systems since the 1970s. Despite evidence of the important benefits of repeat antenatal steroids given to pregnant mothers at risk of delivering before 32 weeks, many doctors have been reluctant to use the treatment more than once due to fears the baby could be at more risk of developing long-term conditions like diabetes and heart disease.
Lead researcher, Dr Chris McKinlay of Auckland University's Liggins Institute said the study was the first to show the repeat steroid doses were safe, and doctors could be reassured the risk of health problems was low.
"With few treatments available for mothers at risk of preterm birth, this is an important finding," said Dr McKinlay.
"Forty percent of pregnant women at risk of having a premature birth and given a dose of antenatal steroids do not deliver immediately, and we wanted to know if giving repeat doses to these women improved outcomes for their babies without causing harm."
The study examined the cardiovascular and metabolic function of almost 260 premature children of school age, who were exposed to repeat steroids or a placebo treatment before birth.
Researchers found the repeat dose of antenatal steroids did not increase risk factors for cardiovascular and metabolic diseases at early school age.
“The study shows that the treatment is safe,” says Dr McKinlay.
“Clinicians wishing to use repeat antenatal steroids can be reassured that the risk of future cardiovascular and metabolic disease from this therapy is low.”
Dr McKinlay said the benefits of antenatal steroids for premature babies were many - they reduced the risk of lung disease, the need for a ventilator, infection, serious gut complications, and bleeding into the brain.
Antenatal steroids are given to a pregnant woman at risk of premature delivery, to mature her baby’s organ systems, especially the lungs, gut and cardiovascular and immune systems, which remain very immature until around 32 weeks and don’t mature fully until after 36 weeks.
Antenatal steroids reduce the risk of preterm lung disease in premature babies, and the need for a ventilator, infection, serious gut complications, and bleeding into the brain.
“All these factors combine to improve survival and prevent serious illness in preterm babies. Steroids such as betamethasone and dexamethasone cross the placenta into the babies’ blood stream to act directly on fetal organs and cells,” says Dr McKinlay.
“These synthetic steroids work by mimicking what normal happens in late pregnancy when the baby’s natural steroid levels rise. This sends a signal to the fetal organs that it’s time to start getting ready for life outside the womb.”
Dr McKinlay said steroids were still the most important treatment for premature babies, and have had a big impact on reducing complications in preterm babies.
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