Objective: To study the prevalence of high-grade cervical intraepithelial neoplasia (CIN) or worse in southern Thai women with atypical squamous cells of undetermined significance (ASC-US) from cervical cytology.

Materials and Methods: The present study was a retrospective cross-sectional analytic study. Medical records from outpatient clinic of Department of Obstetrics and Gynecology between January 1, 2012 and October 31, 2017 were reviewed. Statistical analyses were performed.

Results: Prevalence of high-grade CIN or worse in women with ASC-US from cervical cytology was 14.4%. Of these, 12.4% were high-grade CIN and 2.0% were cervical cancer. Multiple sexual partners was significantly associated with underlying high-grade CIN or higher (p<0.01).

Conclusion: Prevalence of high-grade CIN or worse in southern Thai women with ASC-US from cervical cytology was 14.4% and multiple sexual partners was significantly associated with underlying high-grade CIN or worse in the present population.

Keywords: Atypical squamous cells of undetermined significance (ASC-US), Cervical carcinoma, High-grade CIN