Also , women using fennel ( 73 % ) and LD-COC ( 65 % ) were significantly more likely than those using placebo ( 31 % ) to have subsequent DMPA injection [ RR 2.5 ( 95 % CI 1.3 to 4.9 ) and RR 2.0 ( 95 % CI 1.1 to 3.7 ) , respectively ] .