 The attribution of the treatments will be carried out by drawing lot, according to a procedure in double blind as of the established diagnosis of the fetal infection. In the absence of reference treatment, a placebo will be employed in the reference group. The patients included will be thus placed in one of the 2 parallel groups. The observance will be evaluated. Taking into consideration our preliminary study, a difference of 20 between the 2 groups can be discounted. The number calculated of subjects to include in the test in order to guarantee a power of 80 to him is of 82 in each group. Recruitment will be carried out in a multicentric way. The necessary duration of inclusion will be 36 months 