More on the 2-Day Method ...

"A clinical trial that followed 450 women in Guatemala, Peru and the Philippines, for up to thirteen cycles of TwoDay Method use, found that the method is highly effective. First year life-table pregnancy rate for correct use was 3·5. When all cycles and all pregnancies were included in the analysis, the pregnancy rate was 13·7 (Arévalo et al., 2004)."