BACKGROUND The aim of this study was to evaluate a correlation between PROM and genital infections. METHODS A total of 308 vaginal swabs were made in randomized study group composed by 184 pregnant women aged between 26 and 32 years with an extreme age of 19 (one) and 40 years (one). Three vaginal swabs and one cervical swab (searching for Chlamydia) were made for every patient. Sixteen patients were excluded during this study, because they decided to have their babies in other hospitals. Therefore, the patients totally included in the study were 166: 109 at the first pregnancy, 33 at the second pregnancy and 5 at the third pregnancy. No one of them had any spontaneous abortion in the past. All possible other factor which ca be considered responsible and/or inductive of premature ruptures, such as cervical incontinence, cigarette smoke and coitus were excluded. RESULTS 280 vaginal swabs were made in this study: 134 were positive, with a global positivity percentage of 47.85%. Premature rupture of membranes (PROM) was observed in 38 cases with an incidence of 23.03%: 26 were PROM and 12 were pPROM. The extreme pPROMs occurred, respectively, at the 21st and at 34th gestational week; 29 of the 38 cases of PROM, were associated with positive cultures. The results obtained show an evident correlation between PROM and Ureaplasma urealyticum vaginosis: this fact is improved by the high incidence percentage of this mycobacter in pregnant women and also by an absolute predomination of Ureplasma urealyticum in PROM cases (72.41%). CONCLUSIONS These data obtained confirm the importance of this microorganism in PROM genesis, according to some recent studies. It is suggested that Ureaplasma urealyticum infection can contribute to a premature start of labour.