Natural history of histologically confirmed high-grade cervical intraepithelial neoplasia during pregnancy: meta-analysis

OBJECTIVES: This study aimed to conduct a meta-analysis of estimates of the natural history of high-grade cervical intraepithelial neoplasia (CIN) during pregnancy. SETTING: Studies examining the clinical courses of histologically confirmed high-grade CIN during pregnancy. PARTICIPANTS: We searched PubMed, Web of Science and Embase for eligible studies. Studies were included if they reported the data regarding the natural history of histologically confirmed high-grade CIN during pregnancy. Final estimates were from the meta-analysis of 10 eligible studies. PRIMARY OUTCOME MEASURES: The regression rate, persistence rate and progression rate of histologically proven untreated high-grade CIN during pregnancy. RESULTS: A total of 10 original studies were included in this meta-analysis. During pregnancy, the regression rate, persistence rate and progression rate of high-grade CIN were 40% (95% CI 35% to 45%), 59% (95% CI 54% to 64%) and 1% (95% CI 0% to 2%), respectively. There was moderate heterogeneity among the studies. The results of the subgroup meta-analysis show that the pooled rates of regression and persistence during pregnancy were 59% (95% CI 54% to 65%) and 40% (95% CI 35% to 45%) for CIN2, and 29% (95% CI 25% to 33%) and 70% (95% CI 65% to 73%) for CIN3. CONCLUSIONS: During pregnancy, the majority of histologically confirmed high-grade CIN would be persistent or regressed to lower grade CIN or normal. However, it is still worth noting that a small percentage of high-grade CIN would progress to cervical cancer during pregnancy.