Objective: To verify whether, during the luteal-follicular transition, increased inhibin B production by abnormally large follicles modifies the expected relationship between the number of follicles and peripheral inhibin B and FSH levels.
Design: Prospective study.
Setting: Teaching hospital, France.
Patient(s): A total of 192 normo-ovulatory women.
Intervention(s): Serum inhibin B and FSH levels and numbers and sizes of antral follicles (3-12 mm) were measured on cycle day 3.
Main outcome measure(s): The strength of hormonal-follicular correlations was assessed in two groups formed according to the presence (large follicle group; n = 73) or absence (small follicle group; n = 119) of one follicle measuring >7 mm.
Result(s): Serum inhibin B and FSH levels were correlated with antral follicle counts (r = 0.32 and r = -0.44, respectively). These relationships were significantly weaker in the large follicle group (r = 0.24 and r = -0.28, respectively) than in the small follicle group (r = 0.51 and r = -0.55, respectively).
Conclusion(s): Antral follicle size influences serum inhibin B and FSH levels and alters their expected relationship with the number of antral follicles on day 3. These results contribute to clarifying the controversial role of serum inhibin B and FSH levels in the prediction of ovarian follicular status.
Copyright 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.