High concentrations of lactoferrin in the follicular fluid correlate with embryo quality during in vitro fertilization cycles

Objective: To investigate the level of lactoferrin (LF) in follicular fluid (FF), as well as the correlation between the LF concentration of FF, fertilization rate, and embryo quality. Design: Retrospective study. Setting: In vivo fertilization program at the Showa University of Medicine, Tokyo, Japan. Patient(s): Follicular fluid was obtained from 35 IVF patients, 25-34 years. Intervention(s): In total, 70 FF and serum samples were collected at the time of oocyte harvesting (44 of the oocytes were fertilized, and 26 were not). The LF concentration in FF was assayed via ELISA. Result(s): The mean LF concentration in FF of the fertilized group (500.2 +/- 35.5 ng/mL) was significantly higher than that in the unfertilized group (397.7 +/- 45.1 ng/mL). A positive correlation between follicular size and LF concentration was not found (r = 0.214). However, a high LF concentration in FF was indicative of good embryo quality. Conclusion(s): High LF concentrations in FF correlate with both a high fertilization rate and good embryo quality.