Delivery outcome after cold-knife conization of the uterine cervix

ObjectiveTo estimate the risk for preterm delivery and obstetric complications in women with prior cold-knife conization.MethodsIn a retrospective study, we compared 76 deliveries of 65 women with prior cold-knife conization with the remaining 29,711 singleton deliveries at our institution between 1992 and 2002.ResultsWe found significant shorter duration of pregnancies in the conization group. Delivery prior to 37 weeks was found in 22.4% (n = 17) of the conization group and in 6.6% (n = 1961) of the controls (OR = 4.07 [2.22–7.10], P < 0.001). Preterm premature rupture of the membranes was found in 17.1% (n = 13) of the conization group and in 2.6% (n = 775) of the controls (OR = 7.70 [3.87–14.21], P < 0.001). Birth weight less than 2500 g was found in 18.4% (n = 14) of the conization group and in 7.7% (n = 2280) of the controls (OR = 2.72 [1.40–4.92], P = 0.002). Overall, birth weight in the conization group was not significantly lower (median 3147 g vs. 3287 g, P = 0.115). Cervical tears were found more frequently in the conization group (8.8% [n = 6] vs. 1.3% [n = 236], OR = 7.53 [2.63–17.57], P < 0.001). There was no difference in mode of delivery, duration of labor, head circumference, chorioamnionitis and use of oxytocin.ConclusionCold-knife conization is a risk factor for preterm birth and preterm premature rupture of the membranes and seems to be a risk factor for cervical tears.