1. Increasing uterine receptivity by decreasing estradiol levels during the preimplantation period in high responders with the use of a follicle-stimulating hormone step-down regimen 
Carlos Simón, M.D., Juan J Garcia Velasco, M.D., Diana Valbuena, M.D., Jose A Peinado, M.D., Carlos Moreno, M.D., José Remohí, M.D., Antonio Pellicer, M.D. 
Fertility and Sterility 
Volume 70, Issue 2, Pages (August 1998)
DOI: /S (98)00140-X

2. FIGURE 1
Circulating levels of E2 during the preimplantation period (days 0–6) in patients undergoing the step-down regimen (dashed line) versus the previous failed cycle (solid line). Bars represent means ± SE.
Fertility and Sterility  , DOI: ( /S (98)00140-X)