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 weeks' gestation among 121 women who had a spontaneous preterm birth 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 lactoferrin concentrations between the case patients and control subjects ( P =.18). Only when the highest titers of lactoferrin 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 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, lactoferrin 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); 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 markers of lower genital tract infection. High lactoferrin levels were associated with spontaneous preterm birth but had a very low predictive sensitivity. (Am J Obstet Gynecol 2000;182:631-5.)