[Concentration gradient of cotinine between blood serum and preovulatory follicular fluid].

OBJECTIVES: The aim of the study was to evaluate the blood serum/follicular fluid gradient for cotinine levels in the IVF patients with different levels of the tobacco smoke exposure. MATERIAL AND METHODS: Cotinine levels were measured by means of the double antibody RIA in blood serum (S) and preovulatory follicular fluid (FF) of 45 IVF patients undergoing standard controlled ovarian hyperstimulation. Self reported smoking status was used for grouping purposes. RESULTS: Mean (range) cotinine concentrations (in ng/ml) in follicular fluid of nonsmokers (n = 10), passive smokers (n = 25) and active smokers (n = 10) were 3.71 (1.20-15.62), 29.65 (20.91-45.75) and 285.69 (62.21-595.00), respectively. The differences were highly significant (p < 0.001). No significant gradient of cotinine concentrations was found between blood serum and follicular fluid. Cotinine levels in serum and follicular fluid were strongly correlated (rs = 0.892; p < 0.001). The S/FF ratio for cotinine levels did not depend on the follicle's size or serum cotinine. CONCLUSION: Cotinine easily crosses the blood/follicle barrier.