title: Predictive value of volume of cervical tissue removed during LLETZ on subsequent preterm delivery: a cohort study.
abstract: OBJECTIVE
  To evaluate the impact of volume of tissue removed during large loop excision of transformation zone on subsequent preterm birth rates.
  
  
  METHODS
  A retrospective cohort study was carried out in a single, large tertiary referral unit in UK. A total of 556 women who delivered between January 2008 and December 2011 following a previous large loop excision of transformation zone procedure or punch biopsy were identified from the maternity and colposcopy databases. Demographic data, gestational age at delivery, birthweight, neonatal outcome and dimensions of excised cervical specimen were collected. Pregnancy outcomes for women who had a previous loop excision were compared to a matched control group who had undergone punch biopsies only.
  
  
  RESULTS
  There was a significant increase in preterm birth rate in the large loop excision group compared to the control group (9.0% vs. 3.6%, respectively, RR 2.5, 95% CI 1.224-5.107). Women who had undergone at least one previous loop excision had more than a threefold increased risk of spontaneous preterm birth compared with their matched controls. However, no relationship between volume or depth of cervical tissue excised and subsequent gestation at delivery could be demonstrated.
  
  
  CONCLUSIONS
  Whilst LLETZ is associated with an increased rate of preterm birth, the volume of tissue removed does not appear to influence the subsequent gestational age at delivery. This should reassure clinicians who should continue to perform LLETZ with adequate tissue margins to ensure complete resection of disease.
authors.affiliation: Department of Obstetrics and Gynaecology, Royal Lancaster Infirmary, Ashton Road, Lancaster LA1 4RP, United Kingdom; Department of Obstetrics and Gynaecology, Royal Victoria Hospital, Newcastle-upon-Tyne, United Kingdom. Electronic address: sarahkitson@doctors.net.uk.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Kitson
authors.affiliation: Department of Obstetrics and Gynaecology, Royal Lancaster Infirmary, Ashton Road, Lancaster LA1 4RP, United Kingdom; Department of Obstetrics and Gynaecology, Royal Victoria Hospital, Newcastle-upon-Tyne, United Kingdom.
authors.forename: Emma
authors.initials: E
authors.lastname: Greig
authors.affiliation: Department of Obstetrics and Gynaecology, Royal Lancaster Infirmary, Ashton Road, Lancaster LA1 4RP, United Kingdom; Department of Obstetrics and Gynaecology, Royal Victoria Hospital, Newcastle-upon-Tyne, United Kingdom.
authors.forename: Enid
authors.initials: E
authors.lastname: Michael
authors.affiliation: Department of Obstetrics and Gynaecology, Royal Lancaster Infirmary, Ashton Road, Lancaster LA1 4RP, United Kingdom; Department of Obstetrics and Gynaecology, Royal Victoria Hospital, Newcastle-upon-Tyne, United Kingdom.
authors.forename: Marie
authors.initials: M
authors.lastname: Smith
mesh_terms: D000328:Adult; D001706:Biopsy / Q000379:methods*; D002277:Carcinoma / Q000473:pathology* / Q000601:surgery; D016022:Case-Control Studies; D002584:Cervix Uteri / Q000473:pathology* / Q000601:surgery; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology*; D012189:Retrospective Studies; D012306:Risk; D065310:Squamous Intraepithelial Lesions of the Cervix / Q000473:pathology* / Q000601:surgery; D062606:Tertiary Care Centers; D002583:Uterine Cervical Neoplasms / Q000473:pathology* / Q000601:surgery; D055815:Young Adult; D002578:Uterine Cervical Dysplasia / Q000473:pathology* / Q000601:surgery
keywords: Large loop excision of transformation zone; Prediction; Preterm birth; Punch biopsy; Volume