RT Journal Article SR Electronic T1 Bleeding patterns after immediate initiation of an oral compared with a vaginal hormonal contraceptive JF Journal of Family Planning and Reproductive Health Care JO J Fam Plann Reprod Health Care FD British Medical Journal Publishing Group SP 22 OP 22 DO 10.1783/147118906775275091 VO 32 IS 1 A1 Andrew Horne YR 2006 UL http://jfprhc.bmj.com/content/32/1/22.3.abstract AB