Objective: This study aimed at assessing the association of the relative risk (RR) of adverse pregnancy outcomes with previous treatment of loop electrosurgical excision procedure (LEEP) for the management of cervical intraepithelial neoplasia (CIN).
Methods: Data sources were from MEDLINE, EMBASE, and SCI citation tracking.
Selection criteria: The eligible studies had data on pregnancy outcomes of women with or without previous treatment for CIN. Considered outcomes were severe preterm delivery (<34/32 weeks), extreme preterm delivery (<28 weeks), low birth weight (<2,500 g), stillbirth, preterm spontaneous rupture of membranes, perinatal mortality, and neonatal mortality and induction.
Results: 36,954 cases and 1,794,174 controls in 4 prospective cohort and 22 retrospective studies were included in this meta-analysis. LEEP was associated with a higher risk of severe preterm delivery (<32 weeks, relative risk 1.98, 95% CI [1.31, 2.98] 159/11,337 vs. 7,830/860,883), extreme preterm delivery (<28 weeks, RR, 2.33, 95% CI [1.84, 2.94] 97/9,611 vs. 1,559/618,332), preterm premature rupture of the membranes (RR, 1.88, 95% CI [1.54, 2.29] 126/2,837 vs. 7,899/313,094), and low birth weight (<2,500 g, RR, 2.48, 95% CI [1.75, 3.51] 110/1,451 vs. 55/1,742). A cervical length of less than 3 cm was significantly increased in LEEP as compared with that of control group (RR, 4.88, 95% CI [1.56, 15.25]), but increasing LEEP volume or depth was not associated with an increased rate of preterm birth <37 weeks. And LEEP was not associated with a significantly increased risk of perinatal mortality, cesarean section, stillbirth mortality, neonatal mortality, induction, and neonatal intensive care unit admission.
Conclusions: LEEP is associated with an increased risk of subsequent preterm delivery (<32/34, <28 weeks) and other serious pregnancy outcomes. But increasing LEEP volume or depth is not associated with an increased rate of preterm birth.