Willow

Here is one thing I found online: "The paramedics arrive, and pronounce Willow dead at the scene. Nick is visibly upset and tells them that she’s pregnant with Shawn Brady’s child. The cops agree to tell Bo Brady the news and tell Nick that they think that things look to be more than just an accident. They have to take Nick in."

But, another site says this: "An autopsy confirmed that Shawn Brady was not the father of her baby. The baby’s father was unknown."

Here is more info on Willow:

Willow Stark was played by Annie Burgstede from October 2006 to June 2007. Willow was a former prostitute who Shawn Brady met one evening. Shawn got Willow a job at Chez Rouge and started dating her after he broke up with his ex-wife Mimi Lockhart. She became more controlling and obsessed with Shawn and disliked that Shawn tried to see Claire or Belle. Shawn broke things off with her so he could be a better father so she set fire to his loft. Weeks later, EJ Wells paid her to break into the Brady home and she accidentally set fire to the place. She planted Chelsea Brady‘s brush at the scene, but Nick Fallon hid the brush, so she was sent to jail. Once Nick bailed her out, he helped her find a place to live. Willow attempted to blackmail Nick and eventually fell to her death on an episode that aired June 5, 2007. She has a younger brother named Jed Stark who attended Salem University.