Hi, Thanks for using HCM.
Yes there are chances, once embryo is transferred into uterine cavity
, it will be freely moving, it needs to get attached to uterine cavity for implantation
, which takes 3 to 4 days for complete attachment.
You can get USG abdomen done.
Small solid mass could be a blood clot, need not always embryo.
Consult your doctor for examination and management.
Hope I answered your question. Feel free to ask me if you have any further queries.
Wish you good health. Take care.