A federal judge in Indiana late on Monday blocked the execution of Lisa Montgomery, a convicted murderer and the only woman on federal death row in the United States, on mental health grounds, based on evidence that she was unable to understand the government's rationale for her execution.
The decision was later upheld by the US Court of Appeals for the District of Columbia circuit, pushing any new execution date into Joe Biden's administration unless the Supreme Court intervenes.
Montgomery, who was due to be killed by lethal injection on Janua. 12, was convicted in 2007 in Missouri for kidnapping and strangling Bobbie Jo Stinnett, then eight months pregnant. Montgomery then cut Stinnett's foetus from the womb. The child survived.
US judge James Patrick Hanlon granted a stay of execution to allow the court to conduct a hearing to determine whether she is competent to be executed, according to a court filing made in the US district court of Southern District of Indiana.
Montgomery's lawyer, Kelley Henry, welcomed the judge's ruling and said the court was right to put a stop to her execution.
"Mrs Montgomery is mentally deteriorating and we are seeking an opportunity to prove her incompetence," Henry said in a statement.
Montgomery's lawyers have asked for US President Donald Trump's clemency, saying she committed her crime after a lifetime of being abused and raped. In a nearly 7 000-page clemency petition filed last week, they asked Trump to commute Montgomery's sentence to life in prison.
The lawyers have said Montgomery admits her guilt but deserves clemency because she has long suffered severe mental illness, exacerbated by being gang raped by her stepfather and his friends during an abusive childhood.