Background: To evaluate the accuracy of the decidual phosphorylated isoform of insulin-like growth factor binding protein-1 in endocervical secretions to predict premature delivery in symptomatic and asymptomatic pregnant women.
Methods: The study included 332 pregnant women: 109 symptomatic patients (study group) and 223 asymptomatic women (control group). For all women, qualitative and quantitative assessment of the decidual phosphorylated isoform of insulin-like growth factor binding protein-1 in endocervical secretions was carried out, but the quantitative assay was finally performed in 282 of 332. Student's test, the chi2 test, and Fisher's exact test were used as appropriate.
Results: The phosphorylated insulin-like growth factor binding protein-1 qualitative test was positive in 35 of 301 women (11.6%) and 11 (31.4%) of them delivered before 37 weeks; in the remaining 266 women with a negative test, there were 11 (4.7%) premature deliveries (relative risk = 5.8; 95% CI = 3.3-10.3). The mean values of quantitative phosphorylated isoform of insulin-like growth factor binding protein-1 were 56.9 microg/l (95% CI = 40.7-73.1) in cases of a positive qualitative test and 6.1 microg/l (95% CI = 4.0-8.3; p = 0.0001) in women with a negative result. The sensitivity, specificity, positive predictive value, and negative predictive value for phosphorylated isoform of insulin-like growth factor binding protein-1 test in symptomatic patients were 69.2%, 90.5%, 50%, and 95.6% respectively, while in the asymptomatic patients they were 22.2%, 91.8%, 11.8%, and 96% respectively.
Conclusions: The phosphorylated isoform of insulin-like growth factor binding protein-1 in cervical secretions is a potential specific marker for preterm delivery occurring before 37 weeks. This test may have an important role in the management of women presenting with symptoms suggestive of preterm labour.