Serum and follicular endocrine profile is different in modified natural cycles than in cycles stimulated with gonadotropin and gonadotropin-releasing hormone antagonist.

This study compared serum and follicular anti-müllerian hormone, LH, FSH, E(2), and P concentrations in modified natural cycles and controlled ovarian hyperstimulation cycles to analyze their effect on oocyte and embryo quality and implantation. Follicular anti-müllerian hormone, FSH, E(2), and P concentrations had no effect on embryo quality, whereas high serum and follicular LH concentrations in natural cycles modified only with hCG did not compromise oocyte and embryo quality but might have a negative effect on implantation.