BackgroundTelemonitoring is an alternative to in-person appointments and overcomes geographic distance barriers.ObjectiveThe primary objective of this study was to evaluate adherence to post-molar follow-up using both WhatsApp and in-person appointments compared with standard care. The secondary objective was to evaluate the rate of completion of post-molar follow-up of complete moles, considering 6 and 3 months of duration.MethodsThis retrospective cohort study was conducted at the Gestational Trophoblastic Disease Center, São Paulo Hospital. Patients with complete or partial mole treatment between January 1, 2009 and December 31, 2018 were included in two groups: group 1 (patients from 2009 to 2013) and group 2 (from 2014 to 2018), before and after telemonitoring implementation, respectively. Complete follow-up was considered if after the first normal human chorionic gonadotropin (hCG) level (<5 mIU/mL), the patient was followed up for an additional 30 days (partial mole) or 180 days (complete mole). Loss to post-molar follow-up with positive hCG was also evaluated. Statistical analysis was performed using Pearson’s Χ2 test, 5% significance level (p=0.05), and R version 4.0.2.ResultsA total of 308 patients were included in the study, 92 of them were assessed in group 1 and 216 patients in group 2. There was no difference between the rates of complete follow-up after telemonitoring implementation (complete mole: 42/72=58.3% group 1 vs 85/163=52.1% group 2; p=0.38; partial mole: 16/20=80% group 1 vs 37/53=69.8 group 2; p=0.3), and no increase of loss to post-molar follow-up with positive hCG (8/92=8.7% group 1 vs 14/216=6.5% group 2; p=0.49). The shortening of follow-up of complete moles to 90 days increased the rate of complete post-molar follow-up (from 127/235=54.0% to 189/235=80.4%, p<0.001).ConclusionsThe association of telemonitoring with in-person appointments could have had an advantage in post-molar follow-up since it did not reduce adherence to hormonal surveillance. Shortening post-molar follow-up after complete mole to 90 days after the first normal hCG level increased the rate of complete post-molar follow-up.