Cervix Uteri/pathology; Cytodiagnosis/methods; Papanicolaou Test; Papillomavirus Infections/epidemiology; Pregnancy Complications, Neoplastic/epidemiology; Uterine Cervical Dysplasia/pathology; Uterine Cervical Neoplasms/pathology; Vaginal Smears/methods; Adult; Age Distribution; Ambulatory Care Facilities; Biopsy; Colposcopy/methods; Female; Health Knowledge, Attitudes, Practice; Hospitals, University; Humans; Middle Aged; Papillomavirus Infections/diagnosis; Papillomavirus Infections/pathology; Pregnancy; Pregnancy Complications, Neoplastic/diagnosis; Pregnancy Complications, Neoplastic/pathology; Prenatal Care; Prevalence; Sensitivity and Specificity; Socioeconomic Factors; Thailand/epidemiology; Uterine Cervical Neoplasms/diagnosis; Uterine Cervical Neoplasms/epidemiology; Uterine Cervical Dysplasia/diagnosis; Uterine Cervical Dysplasia/epidemiology