A federal judge in Indiana granted a stay of execution on mental-health grounds to Lisa Montgomery, the only woman on federal death row in the US — though her scheduled Tuesday death sentence remained in the balance.

In granting the stay late Monday, Judge Patrick Hanlon cited the need to determine Montgomery’s mental competence to face execution, the Topeka Capital-Journal reported.

Later Tuesday night, the Supreme Court vacated a separate stay put in place by the US Circuit Court of Appeals for the District of Columbia.

The Supreme Court is also expected to rule on the 8th Circuit stay Tuesday night.

If the Supreme Court clears the second stay, she will be the first federally executed woman in the US since 1953.

Montgomery the so-called “womb raider,” was convicted in 2007 of strangling Bobbie Jo Stinnett in Missouri and then cutting her unborn baby from her womb.