By Sadie Whitelocks

Anti-inflammatory drugs taken by millions of pregnant women around the world may raise the risk of autism in their babies.

A study looked at the impact on children who are exposed to glucocorticoids - a class of steroids - in the womb.

Those prenatally exposed to the drugs were between 30 and 50 percent more likely to be diagnosed with autism compared to children whose mothers did not take them.

The study also linked glucocorticoids - which include prednisone and cortisone - to a higher risk of intellectual disabilities, Attention-deficit/hyperactivity disorder (ADHD) and anxiety.

Glucocorticoids mimic the hormone cortisol, which is produced by the adrenal gland and known for its anti-inflammatory effect.

They are prescribed to pregnant women at risk of preterm births because they also help with the fetus's organ development and maturation.

The drugs are also given to pregnant women suffering from autoimmune or inflammatory disorders such as rheumatoid arthritis, lupus, and asthma because they dampen down the immune response.

However, the new study suggests if babies are exposed to excess amounts of glucocorticoids it can alter their brain development in a negative way.

It is estimated two to three percent of the population are currently prescribed glucocorticoids.

And in the US, the most common glucocorticoid drugs are prednisone, triamcinolone acetonide, and methylprednisolone.

The steroids betamethasone and dexamethasone, which pass through the placenta, are used in people at risk of preterm delivery and both are usually injected into the mother's arm, leg, or buttocks.

Some side effects of prolonged glucocorticoid use have been known for decades, the most common being weight gain and the joint disease osteoporosis.

But the latest body of research out of Denmark suggests the drugs could also harm the developing brains of babies.