1. Frequency and effect of vaginal bleeding on pregnancy outcome during the first 3 weeks after positive β-hCG test results following IVF-ET 
Glen E Hofmann, M.D., Ph.D., Cindy L Gundrum, R.N., Lisa M Drake, Ann B Bertsche, R.N. 
Fertility and Sterility 
Volume 74, Issue 3, Pages (September 2000)
DOI: /S (00)

2. Figure 1
Incidence of vaginal bleeding and obstetric outcome in 196 women with serially increasing β-hCG levels. The left panel shows the frequency of vaginal bleeding in the entire study population regardless of obstetric outcome. The right panel indicates the incidence of live birth in women with (black bars and those without (gray bars) vaginal bleeding in the first 3 weeks after a positive β-hCG test result. Significantly more women with vaginal bleeding experienced pregnancy loss. ∗P<
Hofmann. Early vaginal bleeding and IVF outcome. Fertil Steril 2000.
Fertility and Sterility  , DOI: ( /S (00) )