title: Progesterone-to-follicle index is better correlated with in vitro fertilization cycle outcome than blood progesterone level.
abstract: OBJECTIVE
  To investigate the impact of late follicular phase progesterone (P) elevation in relation to ovarian response on cycle outcome.
  
  
  METHODS
  Cohort study. The progesterone-to-follicle index (PFI) was calculated by dividing the blood P by the number of follicles ≥14 mm. The clinical pregnancy rate was calculated against the range of PFI values and blood P levels.
  
  
  METHODS
  In vitro fertilization unit.
  
  
  METHODS
  A heterogenous population undergoing IVF with pituitary suppression and gonadotropin stimulation resulting in 3-15 follicles ≥14 mm and blood P≤10 nmol/L on hCG day and resulting in fresh embryo transfer.
  
  
  METHODS
  None.
  
  
  METHODS
  Association of blood P and PFI with clinical pregnancy rate.
  
  
  RESULTS
  Data were retrieved for 8,649 IVF cycles in normal responders. The (reverse) odd ratios for pregnancy were 1.112 (95% confidence interval [CI], 1.077-1.165) for blood P and 4.104 (95% CI, 3.188-5.284) for the PFI. Elevated P levels were associated with a lower pregnancy rate only when they reached the >93rd percentile. The PFI was inversely and linearly related to the pregnancy rate for the whole range of values.
  
  
  CONCLUSIONS
  A late increase in P level is detrimental if it is a consequence of increased P production per follicle (high PFI) but not if it is a consequence of additional follicular recruitment. The PFI enables clinicians to differentiate these conditions.
authors.affiliation: Infertility and IVF Unit, Beilinson Women's Hospital, Rabin Medical Center, Petach Tikva, Israel. Electronic address: yoelsh1@clalit.org.il.
authors.forename: Yoel
authors.initials: Y
authors.lastname: Shufaro
authors.affiliation: Infertility and IVF Unit, Beilinson Women's Hospital, Rabin Medical Center, Petach Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Onit
authors.initials: O
authors.lastname: Sapir
authors.affiliation: Infertility and IVF Unit, Beilinson Women's Hospital, Rabin Medical Center, Petach Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Galia
authors.initials: G
authors.lastname: Oron
authors.affiliation: Infertility and IVF Unit, Beilinson Women's Hospital, Rabin Medical Center, Petach Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Avi
authors.initials: A
authors.lastname: Ben Haroush
authors.affiliation: Infertility and IVF Unit, Beilinson Women's Hospital, Rabin Medical Center, Petach Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Roni
authors.initials: R
authors.lastname: Garor
authors.affiliation: Infertility and IVF Unit, Beilinson Women's Hospital, Rabin Medical Center, Petach Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Haim
authors.initials: H
authors.lastname: Pinkas
authors.affiliation: Infertility and IVF Unit, Beilinson Women's Hospital, Rabin Medical Center, Petach Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Tzippy
authors.initials: T
authors.lastname: Shochat
authors.affiliation: Infertility and IVF Unit, Beilinson Women's Hospital, Rabin Medical Center, Petach Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Fisch
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006305:Health Status Indicators; D006801:Humans; D007247:Infertility, Female / Q000097:blood / Q000175:diagnosis* / Q000628:therapy*; D008875:Middle Aged; D006080:Ovarian Follicle / Q000166:cytology*; D065851:Ovarian Reserve; D011247:Pregnancy; D011374:Progesterone / Q000097:blood*; D011379:Prognosis; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D011374:Progesterone
keywords: IVF; follicle; progesterone; progesterone-to-follicle index