This randomized phase III trial studies how well methotrexate works compared to dactinomycin in treating patients with low-risk gestational trophoblastic neoplasia. Drugs used in chemotherapy, such as methotrexate and dactinomycin, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. It is not yet known whether methotrexate is more effective than dactinomycin in treating gestational trophoblastic disease.