Preterm birth and previous conisation of the cervix

Abstract

Preterm birth and previous conisation of the cervix Sir, The paper from Ørtoft et al.1 demonstrates a hazard to future pregnancy proportional to the length of cervical canal excised at conisation. In the same issue, Van de Vijver et al. 2 further recommend that expectant management of all lesions should be considered in young women.We question, however, whether these findings are relevant to current UK practice.Measuring histological specimen size is difficult, and the technique of transport in saline, opening and stretching before fixation may result in different dimensions from those that we typically see in our practice.The dimensions of the large loop excision of the transformation zone (LLETZ) specimens described by Ørtoft et al. were mean height of 15.8 ± 4.2 mm and mean ectocervical diameter (D = C/p) of 13.2 ± 2 mm. This suggests a long thin cone with a focus on excising the endocervical canal.The vast majority of our patients undergoing the standard outpatient LLETZ procedure have a visible squamocolumnar junction (SCJ), and therefore excision of the transformation zone is effected by a much shallower excision of the order of 8-12 mm in depth. This would have less effect on future pregnancy, and our advice to patients should take account of this.Finally, if one manages all lesions expectantly in young women, why screen them at all? j Preterm birth and previous conisation of the cervix References Authors' ReplySir, We wish to thank Drs Bamford and Hall for some interesting and very relevant comments. 1 We agree with their statement that a small and shallow LLETZ (large loop excision of the transformation zone) cone biopsy may do little or no harm in relation to preterm delivery. The size of a cone can be difficult to measure, which may account for why different studies show different results. However, our study 2 agrees with many others that there is a positive correlation between the depth of the cone and the risk of subsequent preterm delivery, and we think this agreement is unlikely to have occurred by chance. It therefore seems logical that the clinician should try to avoid a deep cone when this can be done without putting women at risk for cervical cancer. Bamford and Hall also speculate that the depth of the cone biopsies in our study was greater than is usual in UK practice. The decision to make a deep or shallow biopsy is related to the colposcopic findings-particularly the location of the transformation zone, the severity of the dysplasia and the histology-as for example with adenocarcinoma in situ. In our study the indications for cone biopsy were cervical intraepithelial neoplasia, stage 3 (CIN3) for 89% of cases and, CIN1 or 2 in only 11% of the women. Only lesions located in a visible transformation zone were treated conservatively. The severity of the lesions seen in our practice may have caused us to make wider and deeper cones, and thereby created a higher risk of preterm delivery. However, this risk is likely to represent a continuum rather than be 'all or nothing'. The fact that we r...