Before discontinuation of the placebo treatment group in July 2011 , the occurrence of pregnancy loss ( 96 of 288 pregnancies ) was 42.5 % for women receiving FTC+TDF compared with 32.3 % for those receiving placebo ( difference for FTC+TDF vs placebo , 10.2 % ; 95 % CI , -5.3 % to 25.7 % ; P = .16 ) and was 27.7 % for those receiving TDF alone ( difference vs placebo , -4.6 % ; 95 % CI , -18.1 % to 8.9 % ; P = .46 ) .