title: Follicle pool, ovarian surgery and the risk for a subsequent trisomic pregnancy.
abstract: OBJECTIVE
  Is there an association between trisomic pregnancy, a marker for decreased oocyte quality, and the reduced oocyte quantity that follows ovarian surgery?
  
  
  CONCLUSIONS
  Previous ovarian surgery is not associated with an increased risk for a subsequent trisomic pregnancy.
  
  
  BACKGROUND
  Ovarian surgery diminishes the number of oocytes. The risk for a trisomic pregnancy is suggested to be higher in women with fewer oocytes, independent of their chronological age.
  
  
  METHODS
  This is a matched case-control study. Cases are women with a confirmed trisomic pregnancy occurring between 1 January 2000 and 31 December 2010 regardless of pregnancy outcome and controls are women that had a live born child without a trisomy. In total, there were 8573 participants in the study; 1723 cases and 6850 controls.
  
  
  METHODS
  Data were obtained from Danish medical registries. Matching criteria were maternal age and year of conception. Number of controls matched per case ranged from one to four. Among cases and controls with a trisomic pregnancy, 2.7% (46/1723) versus 2.5% (172/6850) had undergone ovarian surgery before pregnancy.
  
  
  RESULTS
  History of ovarian surgery is not associated with a higher risk for a subsequent trisomic pregnancy (odds ratio = 1.00, 95% confidence interval 0.99-1.01). Subgroup analyses by indication of surgery and interval between ovarian surgery and pregnancy do not show an effect on trisomic pregnancy risk.
  
  
  CONCLUSIONS
  The medical registries used to select cases and controls did not contain information on surgical technique nor volume of ovarian tissue resected, previous trisomic pregnancy prior to the ovarian surgery or long-term use of oral contraceptives. Therefore, correction for these factors was not performed.
  
  
  CONCLUSIONS
  We did not confirm the hypothesis that ovarian surgery, a marker for decreased oocyte quantity, is related to trisomic pregnancy, a marker for decreased oocyte quality. This suggests that ovarian surgery, which has a direct reductive effect on the size of the follicle pool, may affect oocyte quality differently when compared with the reduction in follicle pool size due to ageing.
  
  
  BACKGROUND
  The study was supported by grants from the Gratama Stichting, University of Groningen and the University Medical Center Groningen, The Netherlands. Ø.L. has within the last 3 years received honoraria for speeches in pharmacoepidemiological issues, not related to this study. The Department of Obstetrics and Gynaecology receives unrestricted educational grants from Ferring Pharmaceuticals. A.H. received a grant from ZonMW (i.e. National Dutch Scientific funding) for a RCT not related to this publication. Dr A.H. received speakers fee from MSD for an educational presentation. All other authors have no conflict of interest.
authors.affiliation: Department of Epidemiology, HPC FA40, University of Groningen, University Medical Center Groningen, P.O. Box 30001, 9700 RB Groningen, The Netherlands Department of Obstetrics and Gynaecology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: T C
authors.initials: TC
authors.lastname: Honorato
authors.affiliation: Fertility Clinic, Rigshospitalet, University of Copenhagen, København, Denmark.
authors.forename: A A
authors.initials: AA
authors.lastname: Henningsen
authors.affiliation: Department of Clinical Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: M L
authors.initials: ML
authors.lastname: Haadsma
authors.affiliation: Department of Obstetrics and Gynaecology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: J A
authors.initials: JA
authors.lastname: Land
authors.affiliation: Department of Obstetrics and Gynaecology, Hvidovre Hospital, University of Copenhagen, København, Denmark.
authors.forename: A
authors.initials: A
authors.lastname: Pinborg
authors.affiliation: Gynecological Clinic, Rigshospitalet, University of Copenhagen, København, Denmark.
authors.forename: Ø
authors.initials: Ø
authors.lastname: Lidegaard
authors.affiliation: Department of Epidemiology, HPC FA40, University of Groningen, University Medical Center Groningen, P.O. Box 30001, 9700 RB Groningen, The Netherlands t.de.carvalho.honorato@umcg.nl.
authors.forename: H
authors.initials: H
authors.lastname: Groen
authors.affiliation: Department of Obstetrics and Gynaecology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Hoek
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D013509:Gynecologic Surgical Procedures / Q000009:adverse effects; D006801:Humans; D008423:Maternal Age; D016017:Odds Ratio; D006080:Ovarian Follicle / Q000166:cytology*; D065851:Ovarian Reserve; D010053:Ovary / Q000601:surgery*; D011247:Pregnancy; D011256:Pregnancy Outcome; D012307:Risk Factors; D014314:Trisomy
keywords: oocyte pool; ovarian reserve; ovarian surgery; trisomic pregnancy; trisomy