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 cervical lactoferrin concentration, other cervical markers potentially related to infection, and spontaneous preterm birth. Study Design: Cervical lactoferrin concentrations obtained at 22 to 24 weeksʹ gestation among 121 women who had a spontaneous preterm birth <35 weeksʹ gestation were compared with cervical lactoferrin concentrations among 121 women matched for race, parity, and center who were delivered at ≥37 weeksʹ gestation. Results were compared against levels of cervical interleukin 6, fetal fibronectin, and sialidase, against cervical length according to ultrasonography, and according to the bacterial vaginosis 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 ≥1:64. There was no significant difference in the overall distributions of lactofenin concentrations between the case patients and control subjects (P = .18). Only when the highest titers of lactofen in were considered were there more women in the spontaneous preterm birth group (61121 vs 0/121; P = .03). According to Spearman correlation analyses the cervical lactoferrin concentrations were straggly related to interleukin 6 concentration (r = .51; P = .0001), sialidase activity (r = .38; P = .0001), and bacterial vaginosis (r = .38; P = .0001), were weakly related to fetal fibronectin (r = .16; P = .01), and were not related to cervical length. With the 90th percentile (a dilution of 1:32) used as a cutoff to establish a dichotomous variable, lactofenin concentration had the following odds ratios and 95% confidence intervals for associations with other potential markers of infection: bacterial vaginosis odds ratio, 4.8 (95% confidence interval, 2.2–10.3); 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 interval, 0.2–2.0); chlamydiceis odds ratio, 2.3 (950/6 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 markers of lower genital tract infection. High lactoferrin levels were associated with spontaneous preterm birth but had a very low predictive sensitivity.