The relationship between previous treatment for cervical dysplasia and preterm delivery in twin gestations

To describe the impact of previous cervical surgery on preterm birth prior to 34 weeks in twins.

A retrospective review of twin pregnancies delivered between January 1998 and December 2005 at two institutions was performed. Women with a prior cold knife cone (CKC), loop electrosurgical excision procedure (LEEP), or ablative procedure were compared to a control group of women who had not undergone a previous treatment for cervical dysplasia. The primary outcome was delivery before 34 weeks of gestation.

A total of 876 women met inclusion criteria. Of these, 110 (12.6%) had previous surgical procedures for cervical dysplasia, including CKC (n = 10), LEEP (n = 36), cryotherapy (n = 59) and CO2 laser treatment (n = 5). Delivery prior to 34 weeks was more common in women with a previous CKC compared to women with no prior treatment (40% versus 11.3%; odds ratio [OR], 3.6; 95% confidence interval [CI], 1.7-8.0). Delivery prior to 34 weeks was not more common in women with a previous LEEP (8.3%; OR, 0.8; 95% CI, 0.3-2.3) or ablative procedure (9.4%; OR, 0.9; 95% CI, 0.4-1.9) in comparison to the untreated group. Adjusting for the potential confounders of age, tobacco use, infertility treatments and previous preterm birth did not change the results.

Previous CKC is associated with delivery prior to 34 weeks while LEEP and ablative procedures are not. CKC should be carefully considered and avoided when possible in reproductive age women.