The Preterm Prediction Study: Cervical lactoferrin concentration, other markers of lower genital tract infection, and preterm birth

OBJECTIVE: This study was undertaken to determine the relationship among ce rvical lactoferrin concentration, other cervical markers potentially relate d to infection, and spontaneous preterm birth. STUDY DESIGN: Cervical lactoferrin concentrations obtained at 22 to 24 week s' gestation among 121 women who had a spontaneous preterm birth <35 weeks' gestation were compared with cervical lactoferrin concentrations among 121 women matched for race, parity, and center who were delivered at greater t han or equal to 37 weeks' gestation. Results were compared against levels o f cervical interleukin 6, fetal fibronectin, and sialidase, against cervica l length according to ultrasonography, and according to the bacterial vagin osis Gram stain score. RESULTS: Cervical lactoferrin concentrations ranged from not measurable (19 % of the concentrations were below the threshold for this assay) to a titer of greater than or equal to 1:64. There was no significant difference in t he overall distributions of lactoferrin concentrations between the case pat ients and control subjects (P=.18). Only when the highest titers of lactofe rrin were considered were there more women in the spontaneous preterm birth group (6/121 vs 0/121; P=.03). According to Spearman correlation analyses the cervical lactoferrin concentrations were strongly related to interleuki n 6 concentration (r=.51; P=.0001), sialidase activity (r=.38; P=.0001), an d bacterial vaginosis (r=.38; P=.0001), were weakly related to fetal fibron ectin (r=.16, P=.01), and were not related to cervical length. With the 90t h percentile (a dilution of 1:32) used as a cutoff to establish a dichotomo us variable, lactoferrin concentration had the following odds ratios and 95 % confidence intervals for associations with other potential markers of inf ection: bacterial vaginosis odds ratio, 4.8 (95% confidence interval, 2.2-1 0.3); interleukin 6 concentration odds ratio, 2.8 (95% confidence interval, 1.2-6.5); sialidase activity odds ratio, 5.5 (95% confidence interval, 2.2 -13.7); fetal fibronectin concentration odds ratio, 0.6 (95% confidence int erval, 0.2-2.0); chlamydiosis odds ratio, 2.3 (95% confidence interval, 0.8 -6.9); and short cervix odds ratio, 0.5 (95% confidence interval. 0.2-1.4). CONCLUSIONS: Lactoferrin found in the cervix correlated well with other mar kers of lower genital tract infection. High lactoferrin levels were associa ted with spontaneous preterm birth but had a very low predictive sensitivit y.