In the first month after treatment, serum β-HCG levels were measured weekly; in the second to third months, serum β-HCG levels were measured every 2 weeks; in the fourth to ninth months, serum β-HCG levels were measured monthly; Zhao Jun of the Department of Gynecology, Peking Union Medical College Hospital (PUMCH) In the tenth to fifteenth months, serum β-HCG levels were measured every 2 months; thereafter, serum β-HCG levels were measured every 3 months for a total of three years; from the third year onward, serum β-HCG levels were measured biannually for a total of five years; and from five years onwards, serum β-HCG levels were monitored annually for the rest of the life.