Severe PPH occurred in 20 ( 3.6 % ) and 15 ( 2.7 % ) participants in the misoprostol and oxytocin groups , respectively ( RR 1.33 , 95 % CI 0.69 to 2.58 , p = 0.391 ; absolute risk difference 0.9 % , 95 % CI -1.12 to 2.88 ) .