Fetal fibronectin as a marker for an imminent (preterm) delivery. A new technique using the glycoprotein lectin immunosorbent assay.

We have developed a new 'glycoprotein lectin immunosorbent assay' (GLIA) which permits the obstetrician to identify accurately pregnant women at risk for preterm delivery. This GLIA uses two lectins for the quantitative detection of glycosylation variants of fibronectins, namely, Maackia amurensis lectin (MAA) for the detection of fetal fibronectin (fFN), and Sambucus nigra lectin (Elderberry bark lectin; SNA). Fibronectin was quantitated in cervicovaginal secretions, amniotic fluid, and plasma of pregnant women. Detection of fFN in cervicovaginal secretions was considered to indicate a high risk of imminent delivery. The results were as follows: (1) The GLIA could differentiate between pregnant women after the onset of labour and/or with rupture of membranes and women without any signs of an imminent delivery (sensitivity 94%, specificity 96%, p < 0.001). (2) Differentiation was possible between asymptomatic pregnant women delivering within 10 days of sampling or after more than 10 days (sensitivity 93%, specificity 99%; p < 0.001). (3) If fFN was present in the cervicovaginal secretions, delivery occurred within 10 days of sampling irrespective of preterm delivery or delivery at term (p < 0.001). Thus, this GLIA is a useful assay for identifying those asymptomatic pregnant women who will deliver within 10 days of sampling.