The incidence of premature birth is increasing across Canada and around the world. The latest figures indicate approximately 7.8% of all births deliver before 37 completed weeks of pregnancy (full term is 40 weeks). Work begun in New Zealand over 30 years ago indicated that by giving women in premature labour a course of steroids we could improve a premature baby’s outcome. It really wasn’t until the early 1990’s that this became standard practice for women in preterm labour between 24 and 34 weeks gestation.
However, it is the amount of steroids a woman receives that is key. As I wrote in an article published in the Lancet in 2000, women began to receive repeated or multiple doses of steroids (betamethasone or dexamethasone); studies done on animals suggested this was a potential problem and subsequent human studies confirmed that more was not better. The practice of giving pregnant women in premature labour repeated or multiple doses of steroids has essentially stopped.
Yes, steroids during pregnancy are not without potential risk. But the benefits to a premature baby outweigh any small potential risk. When administered properly to women in premature labour, a single course of steroids (2 doses of betamethasone or 4 doses of dexamethasone over 48 hours) can improve a baby’s chance of survival and decrease the chance of respiratory distress syndrome and a bleed into the brain.
We are always looking for ways to improve a baby’s chance of survival while also decreasing the chance of long-term health problems. In a recent advancement it was discovered that giving mothers a dose of Magnesium shortly before delivery may help protect the baby’s brain and decrease the chance of developing cerebral palsy. Current guidelines in countries around the world suggest physicians should consider this treatment and talk to their patients about it.
An article was recently published in the Globe & Mail identifying that babies exposed to steroids AFTER delivery had changes in their brain development; specifically brain volumes seen on MRI scans. This is important and supports other observational studies that have been published over the last several years that have shown the use of steroids after delivery (dexamethasone) is associated with an increased risk of future cerebral palsy (a non-progressive injury to the brain). This drug is no longer used to treat premature babies’ lung problems due to the results of these studies. Researchers did not find any adverse effect on a baby’s brain growth if steroids were used BEFORE delivery.
So what does this all mean? Premature babies are very fragile and are born at extremely important times in their development, including brain development. While our ability and technology to keep babies alive gets better and better (we have pushed the limit of viability back to 23 weeks gestation) some of what we do to keep a baby alive may have adverse effects on the baby.
Babies that are born prematurely - regardless of whether they have been exposed to steroids or not - have a greater risk of brain development issues. The risk is greater the more premature the baby. For women in premature labour, or who need to deliver prematurely (between 24 and 34 weeks gestation) for maternal or baby reasons, a single course of steroids is of real benefit and should be considered given that it does offer real benefits to the baby. However, use of repeated or multiple courses of steroids before delivery or use of steroids after delivery should not be occurring routinely and the risks/benefits certainly need to be thoroughly discussed with the parents.