What can be causing my hcg levels to fluctuate greatly and have symptoms of miscarriage but the fetus has been seen in my uterus?

Fluctuating hcg: Fluctuated levels of hcg is not a reassuring sign. The simple fact is that just because the fetus is in the uterus does not mean she is not miscarrying. Sometimes a spontaneous abortion is followed by spontaneous delivery of the fetus but other times the fetus must be delivered by the doctor. Follow up with her OB and he/she will advise her.