title: Are cause of subfertility and in vitro fertilization treatment risk factors for an earlier start of menopause?
abstract: OBJECTIVE
  To study whether women diagnosed with unexplained subfertility reach the menopause transition and natural menopause earlier than women with tubal subfertility, in an in vitro fertilization (IVF)-treated population, and to examine the influence of the number of IVF cycles on the occurrence of an early menopause transition and natural menopause.
  
  
  METHODS
  This retrospective cohort study included 12 IVF clinics in the Netherlands. A nationwide retrospective cohort study was conducted among women whose first IVF cycle was stimulated with gonadotrophins in the Netherlands between 1983 and 1995 (n = 7,842). Most of the women were in their late 30s at the end of the follow-up period (range 24-55 y). The main outcome measures were the relative risk (RR) of having reached natural menopause and the risks (RR) of having entered the menopause transition or natural menopause according to the cause of subfertility and the number of IVF cycles.
  
  
  RESULTS
  Women with unexplained subfertility did not have an increased risk of entering the menopause transition or natural menopause (adjusted RR = 0.5; 95% CI, 0.2-1.5; and RR = 0.8; 95% CI, 0.6-1.1). After a 5-year follow-up period, we found no increased risk for entering the menopause transition or natural menopause among women who had undergone six or more IVF cycles when compared with women who had undergone only one IVF cycle (adjusted RR = 0.4; 95% CI, 0.1-1.7; and RR = 0.9; 95% CI, 0.6-1.6).
  
  
  CONCLUSIONS
  Underlying causes of unexplained subfertility do not predispose women to an early start of menopause. Although the number of IVF cycles was not associated with early menopause, longer follow-up is needed.
authors.affiliation: Department of Epidemiology, Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Evelien J
authors.initials: EJ
authors.lastname: de Boer
authors.forename: Isolde
authors.initials: I
authors.lastname: den        Tonkelaar
authors.forename: Curt W
authors.initials: CW
authors.lastname: Burger
authors.forename: Flora E
authors.initials: FE
authors.lastname: van Leeuwen
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007246:Infertility / Q000503:physiopathology* / Q000628:therapy; D008593:Menopause / Q000502:physiology*; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors