In the largest clinical trial ever conducted on the inhaled steroid drug Pulmicort® (budesonide), pregnant women with mild asthma were found to deliver healthy children in similar numbers to those who used a placebo.

The START trial (inhaled Steroid Treatment As Regular Therapy in early asthma) had 7,241 patients from more than 32 countries and aged 5 to 66 years. Of the There were 313 pregnancies among the 2,473 women in the trial. 81% of the women using the drug and 78% of women using a placebo delivered healthy children.  Congenital abnormalities and side effect numbers were similar in both groups. Pulmicort was given in low doses throughout the patients' pregnancies.