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.