THE OUTCOME OF PREGNANCY AFTER CO2-LASER CONIZATION OF THE CERVIX

Objective To investigate the effect of laser conisation of the cervix on the outcome of subsequent pregnancy. Design Case-control study. Set ting Department of Obstetrics & Gynaecology, University Hospital, Tron dheim, Norway. Subjects Three hundred and fifty-one women were treated for cervical intra-epithelial neoplasia (CIN) by laser conisation of the cervix between 1 January 1983 and 31 December 1985. The 56 women a mong them who had been delivered of live infants beyond 22 weeks gesta tion after the conisation and before 1 January 1991 were studied for t he outcome of their pregnancies. For each case, two controls of equal parity and age (+/-3 years) were selected. Main outcome measures The l ength of gestation and birthweight of the infants. Results The median (range) length of gestation was 39 weeks (26-43) in cases compared wit h 40 weeks (34-42) in controls (z = -4.0, P<0.001). The median (range) birthweight was 3330 g (1150-4940) in cases and 3630 g (1610-5080) in controls (z = -3.5, P<0.001). Overall 38% of cases were delivered pre term (less-than-or-equal-to 37 weeks gestation), compared with 6% of c ontrols (P<0.0001; odds ratio 9.0, 95% CI 3.7-21.7). A logistic regres sion analysis of a set of possible confounding factors revealed no sig nificant risk factors in addition to conisation for the occurrence of preterm delivery. No correlation was found between the height of the c one and the occurrence of preterm delivery in subsequent pregnancy. Co nclusion Conisation with microsurgical laser technique increases the r isk of preterm delivery in subsequent pregnancies. Laser conisation in young women should be restricted to those with high grade CIN or a le sion extending into the endocervical canal.