Queensland doctor Caroline de Costa says she's going to stop performing medical abortions.

De Costa has been one of the leading advocates of the abortion drug RU486.

But she says she now fears legal repercussions for herself and her patients.

This week a young Cairns girl and her partner will appear in court for using the drug to have an abortion.

The trial is set to reignite debate over the legality of medically acquired terminations.

Jennifer Richardson reports.