low blood sugar can cause that as well

She could be not driking enough fluids or maybe comming down with something. I had bleeding the first three months of my pregnancy, and I know allot of women who have had there period. Doctors say it could be old blood that needs to get out and they told me that is was comming from my cervix. Take a home test first thing in the morning or I recommend going to a doctor for a blood test that will show for sure if she is carrying the hormone in her body. Good Luck