Figure 1.

Data retrieval of women registered with an HM code in the NPR, the DCR, and the DPR. Two different data sets from DPR were created. ^aFor comparing with the data set from the NPR, three women registered in the NPR and the DPR with >6 months between the dates of registration were excluded. ^bFor comparing with the DCR, seven women registered in the DCR and the DPR with >6 months between the dates of registration were excluded.

Abbreviations: DCR, Danish Cancer Registry; DPR, Danish Pathology Registry; HM, hydatidiform mole; NPR, National Patient Registry.