title: Variability between the follicular steroid hormone levels in different follicles of the same patient and between patients.
abstract: BACKGROUND
  There is disagreement as to whether the concentration of a substance in follicular fluid is related to the quality of the follicle as a possible reflection of the oocyte quality or whether this concentration is related to the clinical characteristics of the patient.
  
  
  OBJECTIVE
  To establish the variability of steroid hormone levels in follicular fluids from different follicles of the same patient and between patients.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  In 31 patients who underwent intracytoplasmic sperm injection it was performed an ultrasound guided aspiration of follicular fluid of the first two mature follicles from each ovary. Chemiluminescent microparticle immunoassays were performed to determine the levels of estradiol, progesterone, testosterone, and dehydroepiandrosterone sulfate (DHEA-S).
  
  
  METHODS
  Unconditional mixed model.
  
  
  RESULTS
  Variation in estradiol levels between follicles in the same patient was approximately twice the variation between subjects (P = 0.05). In the case of progesterone, the intra-subject variation was similar to the inter-subject variation (P = 0.006). The testosterone levels had a slightly smaller intra-subject variation than inter-subject variation (P = 0.002), and the intra-subject variation in DHEA-S levels was approximately one-fifth of the inter-subject variation (P = 0.0003).
  
  
  CONCLUSIONS
  The variations in the levels of follicular progesterone and testosterone were similar between patients and between a given patient's follicles; however, the estradiol levels variability was higher among different follicles. The amount of follicular estradiol may be considered a selection tool between the follicles of a given patient.
authors.affiliation: Departments of Obstetrics, Gynaecology and Reproduction, La Paz University Hospital, Madrid, Spain.
authors.forename: Nayara López
authors.initials: NL
authors.lastname: Carpintero
authors.affiliation: Departments of Obstetrics, Gynaecology and Reproduction, La Paz University Hospital, Madrid, Spain.
authors.forename: Onica Armijo
authors.initials: OA
authors.lastname: Suárez
authors.affiliation: Departments of Obstetrics, Gynaecology and Reproduction, La Paz University Hospital, Madrid, Spain.
authors.forename: Carolina González
authors.initials: CG
authors.lastname: Varea
authors.affiliation: Clinical Analyzes, La Paz University Hospital, Madrid, Spain.
authors.forename: Rubén Gómez
authors.initials: RG
authors.lastname: Rioja
authors.affiliation: Departments of Obstetrics, Gynaecology and Reproduction, La Paz University Hospital, Madrid, Spain.
authors.forename: Carmen Cuadrado
authors.initials: CC
authors.lastname: Mangas
keywords: Androgens; estradiol; follicular fluid; progesterone
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