1. Dramatic declines in implantation and pregnancy rates in patients who undergo repeated cycles of in vitro fertilization with blastocyst transfer after one or more failed attempts 
Bruce S Shapiro, M.D., Kevin S Richter, Ph.D., Dee C Harris, Said T Daneshmand, M.D. 
Fertility and Sterility 
Volume 76, Issue 3, Pages (September 2001)
DOI: /S (01)

2. Figure 1
Scatterplots with linear regression comparing numbers of oocytes retrieved (A, R2 = .42, P<.0001), percentages of oocytes fertilized (B, R2 = .12, P=.019), blastocyst formation rates per 2pn embryo (C, R2 = .05, P=.28), and total numbers of blastocysts produced (D, R2 = .22, P=.020) between first and second cycles.
Shapiro. Fertil Steril 2001.
Fertility and Sterility  , DOI: ( /S (01) )