Underdiagnosis of cervical intraepithelial neoplasia (CIN) 2 or Worse Lesion in Women with a Previous Colposcopy-Guided Biopsy Showing CIN 1.

 Expectant follow-up for biopsy-proven cervical intraepithelial neoplasia (CIN) 1 is the current recommendation for the management of this lesion. Nevertheless, the performance of the biopsy guided by colposcopy might not be optimal. Therefore, this study aimed to calculate the rate of underdiagnoses of more severe lesions in women with CIN 1 diagnosis and to evaluate whether age, lesion extent and biopsy site are factors associated with diagnostic failure.