Before discontinuation of the placebo treatment group in July @ , the occurrence of pregnancy loss ( @ of @ pregnancies ) was @ % for women receiving FTC+TDF compared with @ % for those receiving placebo ( difference for FTC+TDF vs placebo , @ % ; @ % CI , -@ % to @ % ; P = @ ) and was @ % for those receiving TDF alone ( difference vs placebo , -@ % ; @ % CI , -@ % to @ % ; P = @ ) .