Cervical conization and preterm delivery/low birth weight

OBJECTIVE: Evaluate the effect of cervical conization on preterm birth/low birth weight (LBW). DESIGN: A systematic review of the literature using external or internal controls. RESULTS: The typical odds ratio for preterm delivery in women with prior cervical conization using external controls was 3.23 (95% confidence interval 2.29-4.55). Using internal controls the typical odds ratio for LBW was 2.97 (95% confidence interval 1.09-8.05). Using external controls the typical odds ratio for LBW was 2.31 (95% confidence interval 1.33-3.99). CONCLUSION: Women with cervical conization are at higher risk for preterm birth than external controls, and the surgical intervention as such is a major determining factor.