For secondary outcomes the investigators will evaluate rate of prematurity and or Intrauterine growth retardation; changes in mother salivary markers of systemic inflammation; profile of inflammosome in placenta and new born cord blood; lactobacilli, bifidobacteria and streptococcus profile in vagina by RT-PCR (specific primers); changes during the study for oral microbiome Intervention group wil receive L. reuteri Prodentis (L. reuteri DSM 17938 & L. reuteri ATCC PTA 5289 ) at a dose of 2x10^8 Colony Forming Units (CFU). One lozenges is to be taken twice per day (one in the morning and one in the afternoon) giving a total daily dose of at least 4x108 CFU/day since randomization until delivery.