No, she is not required by law to tell you that!! That is just silly!
By law, no. Morally, yes.
Stephanie nailed it on the head!
Calvin of China, PhD
This is not as easy as it sounds. In 43 states, she has a right to her privacy, causing the doctor to be tight lipped. Acording to ethics, she is supposed to tell you. But ethics is normally thrown out of the window. Being your girlfriend, she really needs to tell you. If she does not talk, take steps to protect yourself, which could mean deleting her.