A Bronx woman was found dead in her apartment bathroom after a “large amount of blood loss,” police said.

Cops responding to a 911 call found the body of Tyrah McGregor, 42, at 476 East 187th Street, near Washington Avenue, shortly after 5 p.m. Friday, authorities said.

The city Medical Examiner will determine the exact cause of death.

“It’s unclear what led to her demise,” an NYPD spokesman said Saturday. There are no arrests and the investigation is ongoing.