Background: Gestational diabetes mellitus (GDM) if unmanaged can complicate pregnancy outcomes. Selective screening of GDM is a common policy hence, the need for complete medical records of patients. The extent and pattern that documentation of patients’ records can impact GDM screening-by-telehealth requires elucidation. The aim was to describe the effectiveness of phone contacts on medical records and GDM risk factors among a hospital-based antenatal clinic setting Methods: This was an observational study in which previously reported antenatal records of patients screened for GDM were reviewed for effectiveness of phone contacts to do telehealth, and this was with simultaneous GDM risk assessment. Data were analysed by descriptive frequency counting. Results: On effectiveness of phone details on medical records, 41/98 cases were reached, of which 31.7% have three or more GDM risk factors to fulfil selection criteria for laboratory screening of GDM. Prevalence of risk factors in initial routine data collection (24.9%), previous history assessment (21.3%) and at antenatal monitoring phase (37.8%), Among the 57/98 phone contacts that were unreached, 59.6% are switched off. Conclusions: The observations highlight the need of concerted focus on policy and education, for both staff and patients, to improve documentation of correct and valid telephone details in medical records.