Variability between the follicular steroid hormone levels in different follicles of the same patient and between patients

CONTEXT: 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. AIM: To establish the variability of steroid hormone levels in follicular fluids from different follicles of the same patient and between patients. SETTINGS AND DESIGN: Prospective cohort study. MATERIALS AND 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). STATISTICAL ANALYSIS: 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.