title: Time from cervical conization to pregnancy and preterm birth.
abstract: OBJECTIVE
  To estimate whether the time interval between cervical conization and subsequent pregnancy is associated with risk of preterm birth.
  
  
  METHODS
  Our study is a case control study nested in a retrospective cohort. Women who underwent colposcopic biopsy or conization with loop electrosurgical excision procedure, large loop excision of the transformation zone, or cold knife cone and subsequently delivered at our hospital were identified with electronic databases. Variables considered as possible confounders included maternal race, age, marital status, payor status, years of education, self-reported tobacco use, history of preterm delivery, and dimensions of cone specimen.
  
  
  RESULTS
  Conization was not associated with preterm birth or any subtypes of preterm birth. Among women who underwent conization, those with a subsequent preterm birth had a shorter conization-to-pregnancy interval (337 days) than women with a subsequent term birth (581 days) (P=.004). The association between short conization-to-pregnancy interval and preterm birth remained significant when controlling for confounders including race and cone dimensions. The effect of short conization-to-pregnancy interval on subsequent preterm birth was more persistent among African Americans when compared with white women.
  
  
  CONCLUSIONS
  Women with a short conization-to-pregnancy interval are at increased risk for preterm birth. Women of reproductive age who must have a conization procedure can be counseled that conceiving within 2 to 3 months of the procedure may be associated with an increased risk of preterm birth.
  
  
  METHODS
  II.
authors.affiliation: Department of Obstetrics, Gynecology, and Reproductive Sciences, Division of Maternal Fetal Medicine, University of Pittsburgh School of Medicine, 300 Halket Street, Pittsburgh, PA 15213, USA. himeskp@upmc.edu
authors.forename: Katherine P
authors.initials: KP
authors.lastname: Himes
authors.forename: Hyagriv N
authors.initials: HN
authors.lastname: Simhan
mesh_terms: D000328:Adult; D002584:Cervix Uteri / Q000601:surgery*; D015331:Cohort Studies; D003127:Colposcopy; D019092:Conization; D004598:Electrosurgery; D005260:Female; D005306:Fertilization; D006801:Humans; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology*; D012189:Retrospective Studies; D013997:Time Factors