A total of 3,324 singleton pregnant women were screened for pre-term delivery and 128 women were finally randomised and analysed for outcome showing borderline cervical length (25-29 mm) and elevated cervico-vaginal interleukin 6 levels. To verify if vaginal administration of lactoferrin might have an influence on these variables, two groups of 64 patients were formed. Study cases were submitted to lactoferrin for 21 days; controls received no treatment. An inverse relation was found between interleukin 6 levels and cervical length. On day 30 from the beginning of the treatment, study cases showed a decrease in interleukin 6 levels and an increase in cervical length. A greater number of women with regular uterine contractions and reduced cervical consistency before the 37th week of gestation were found in the controls. Our data show that lactoferrin could play a role in reducing the number of women at risk for pre-term birth for shortened cervical length and elevated interleukin 6 levels.