Slow start to my hcg rise

Katrina
I went and had blood work done on Monday October 31st and they came back at 639 mIU/ml and again on Wednesday November 2nd and they had only went up to 906 mIU/ml. What can this mean? I tested again Monday November 7th and the went up to 3,764 mIU/ml. Anyone else have a similar situation and if so what was your out come?