LONDON (AP) — A British neonatal nurse who was convicted of murdering seven babies and the attempted murder of six others has lost her bid to appeal.

Lucy Letby, 34, had asked for permission to challenge the verdict after she was convicted and sentenced to life in prison last year. A three-judge panel of Britain's Court of Appeal heard the case in April and released its decision on Friday.

“Having heard her application, we have decided to refuse leave to appeal on all grounds and refuse all associated applications,″ Judge Victoria Sharp said. “A full judgment will be handed down in due course.”

A jury at Manchester Crown Court had found her guilty of the crimes, which took place between June 2015 and June 2016 at the neonatal unit at the Countess of Chester Hospital in northwestern England.

Most defendants in British court cases don't have an automatic right to appeal. They must seek permission to appeal on a set of narrowly defined legal issues.