If the B-HCG decreases but then levels off and starts to rise again, then the diagnosis is Gestational Trophoblastic Disease. At this point the patient is reexamined, a chest x-ray obtained and perhaps a scan of the liver. But for sure, the patient needs chemotherapy. This is one case where chemotherapy is given on the basis of a blood test without a tissue diagnosis. If there is B-HCG, and the patient is not pregnant, she must be treated.
Treatment is usually easy.
Then the patient is followed for a year with monthly B-HCG titers. As long as they remain normal everything is normal. After the year is up the patient can become pregnant again. The risk for another molar pregnancy is about doubled. But that is still a small number.