Due to insufficient clinical information, most cervicovaginal smears from pregnant or postpartum women have been screened without regard to pregnancy-related cytological changes. Here, we have reviewed 116 abnormal cervicovaginal smears from 103 pregnant and postpartum women. Initial cytological diagnoses revealed the following: 9 cases of high-grade squamous intraepithelial lesions (HSIL), 8 cases of low-grade squamous intraepithelial lesions (LSIL), 85 cases of atypical squamous cells of undetermined significance (ASCUS), and 14 cases involving atypical glandular cells of undetermined significance (AGUS). 31 cases upon review, involved pregnancy-related cytological changes, comprising 25 cases of decidua cells, 4 cases of Arias-Stella reaction, and 2 cases of cedidual cells coupled with Arias-Stella reaction. Interpretation errors were detected in 14 cases: 13 cases of decidual cells interpreted as either ASCUS favor reactive or ASCUS ruled out HSIL, and one case of Arias-Stella reaction was interpreted as ASCUS ruled out HSIL. Decidual cells and degenerated glandular cells with Arias-Stella reaction can result in diagnostic mistakes. In order to avoid misdiagnosis and unnecessary surgeries, both clinicians and pathologists must be aware of the pregnancy-related cytological changes. The clinician should also always inform the pathologist on the pregnancy status of the patient.