Abstract: Objective：To analyze the association of the treatment safety and the related pregnancy outcomes with previous treatment of the loop electrosurgical excision procedure (LEEP) for cervical intraepithelial neoplasia(CIN). Methods：A thorough search of PubMed, Cochrane Library, CNKI, CBM, Wanfang and CqVip electronic databases was performed. Case-control studies about pregnancy outcomes after previous treatment of LEEP for CIN were collected and meta-analysis was carried out with RevMan 5.3 software. Results：Forty case-control studies including 9 002 patients were enrolled in this study with 4 196 patients in study group and 4 806 patients in control group. For women with previous LEEP for CIN, meta-analysis revealed that: (1)The incidence of miscarriage was significantly increased in study group as compared with that of control group (RR=1.34, 95%CI: 1.14-1.57, P＜0.05), no significant difference was found in the incidence of pregnancy, ectopic pregnancy and induced labor with respect to the first, mid trimester of pregnancy between study group and control group (P＞0.05 each); (2)① For maternal, LEEP was associated with a higher risk of preterm delivery (RR=1.60, 95%CI: 1.37-1.86, P＜0.05), preterm premature rupture of membranes (RR=2.72, 95%CI: 1.46-5.07, P＜0.05), no significant difference was found in the incidence of premature rupture of membranes, cesarean section, placenta previa, postpartum hemorrhage in regard to the perinatal period (the late trimester of pregnancy) between study group and control group(P＞0.05 each); ② For perinatal infants, the incidence of low birth weight was obviously increased in study group (RR=1.35, 95%CI: 1.10-1.66, P＜0.05), no significant difference was found in the incidence of fetal distress, neonatal asphyxia and neonatal mortality during perinatal period between study group and control group (P＞0.05 each); ③ For delivery way and complications, LEEP was not associated with a significantly increased risk of precipitate labour, forceps delivery and vacuum extraction delivery, and cervical laceration (P＞0.05 each). Conclusions：LEEP is associated with an increased risk of miscarriage, preterm delivery, preterm premature rupture of membranes and low birth weight. For CIN patients with fertility preservation, the risk of adverse pregnancy outcomes should be fully informed before LEEP.

Key words: Cervical intraepithelial neoplasia, Electrosurgery, Pregnancy outcomes, Meta-analysis, Loop electrosurgical excision procedure