Pregnant women at high risk for preterm labor from at least 13 weeks of gestation will be tested to detect AVF/BV by taking vaginal smear. Diagnosis will be according to the Nugent score criteria. Treatment will be given according to the results:~Patient with a positive smear for AVF- patients tested positive will be treated with either clindamycin or metronidazole. Following treatment another smear will be taken according to which the patients will be divided into 2 research groups: (1) Assessing the effectiveness of probiotic formula to prevent AVF re-infection (secondary infection) - this group includes patients with normal vaginal flora following antibiotic administration. (2) Assessing the effectiveness of probiotic formula to eradicate AVF - this group includes patients with persistent AVF following antibiotic administration (first and second line). In each group the patients will be divided into a research group which will receive the probiotic formula UREX PLUS (containing L. rhamnosus GR-1and L. reuteri RC-14) and a control group which will receive a placebo twice a day until 36.6 weeks of gestation.~Patient with a negative smear for AVF - in those patients the effectiveness of probiotic formula will be tested for primary prevention. These patients will be divided into a research group which will receive the probiotic formula UREX PLUS and a control group which will receive a placebo twice a day until 36.6 weeks of gestation.~Finally, the colonization of lactobacilli in the vaginal flora will be examined by dividing patients with normal vaginal flora into one group receiving a probiotic capsule containing L. rhamnosus GR-1 and L. reuteri RC-14 twice a day for 2 months and a second group without intervention. After two months the group receiving probiotic capsule will receive no treatment and the second group will receive probiotic capsule containing L. rhamnosus GR-1and L. reuteri RC-14 twice a day for 2 months.
Pregnant women at high risk for preterm labor from at least 13 weeks of gestation will be tested to detect abnormal vaginal flora (AVF) or its severe form - bacterial vaginosis (BV) by taking vaginal smear. Treatment will be given according to the results.