Natural history of cervical intraepithelial neoplasia 1 in primigravida

OBJECTIVES.: The purpose of our prospective cohort study was to determine whether cervical intraepithelial neoplasia (CIN) 1 regresses, persists, or progresses during pregnancy. Eighty-four primigravid patients, ages 16 to 32 years old (mean 26), with no history of abnormal Pap smear, had abnormal Pap test results during their prenatal care between August 1995 and December 1998. The initial Pap results on these patients were: 57 (67.8%) atypical squamous cells of undetermined significance; 21 (25%) low-grade squamous intraepithelial lesions (LSIL); and 6 (7.2%) high-grade squamous intraepithelial lesions. Colposcopy and directed biopsies performed showed: 21(25%) normal; 6 (7.2%) acute cervicitis; 9 (10.7%) chronic cervicitis; 39 (46.4%) CIN 1; 7 (8.3%) CIN 2; and 2 (2.4%) CIN 3. RESULTS.: Thirty-nine patients with LSIL were seen for follow-up colposcopy and biopsy in the second and third trimesters of pregnancy and postpartum. Twenty-eight patients (71.8%) had a repeat normal (regression) as follows: 2 (7.1%) in the second trimester, 4 (14.3%) in the third trimester, and 22 (78.6%) postpartum. Three patients (7.7%) had progression. Eight patients (20.5%) had persistent CIN 1. CONCLUSIONS.: Our study found that more than 70% of CIN 1 was associated with pregnancy regression in primigravidas. Our study suggests the need for postpartum follow-up of all the patients diagnosed with CIN 1 during pregnancy. The follow-up should include a Pap smear. Patients without regression of LSIL by Pap smear at the postpartum visit should be thoroughly investigated and treated.