Hi Dr. My Wife Went In For An U/s Last

Hi Dr. my wife went in for an u/s last week there was an empty gestational sac no fetal pole, measuring at 6.8mm we were told she was about 6 weeks or 7 weeks but according to her last period it came up to 9 weeks. she had blood drawn her HCG level measured at 15k, and 2days later another test measured at 12k. Her Dr. said it was most likely she was going to m/c, but she hasn't had any spotting or bleeding. Do you think she will have a m/c?