<prompt> Least pregnancy failure rate inIUCDOestrogen ProgesteroneOestrogen aloneProgesterone alone  <response>: Oestrogen Progesterone 547-Dutta 6thPregnancy Failure Rate H,W,Y PEARL - INDEXNumber of accidental pregnancies x 1200Number of patients in 100 year1200 Number of months in 100 years Condome 14 IUCD 2 Diaphragm 20 LNG- IUS 0.2 H.W.Y Rhythm method 20-30 1-2 H.W.Y Coitus interruptus 20 OCP Progesterone alone 0.5-2 H.W.Y 