| الوصف: |
Objective: This thesis explores the prediction of preterm delivery in women with symptoms of preterm labour by examination of the putative indicators: fetal fibronectin, vaginal cytokines (Interleukin (IL)-1f, IL-6, IL-8, IL-10 and tumour necrosis factor «a (TNF-«)), and the serum markers corticotrophin releasing hormone (CRH), corticotrophin binding protein (CRH-BP) and activin-A. Cervical dilatation and the Bishop score were further assessed and provided baseline predictive values against which the other predictors were compared. Combinations of the above markers were also investigated. Study Design: Women presenting between 24 and 33° weeks with symptoms of preterm labour and intact membranes were recruited to this prospective cohort study (n=146). Samples of cervicovaginal secretions and serum were obtained shortly following hospital admission, and the prototype bedside dipstick Fetal Fibronectin Membrane Immunoassay test (Adeza, Biomedical) determined fetal fibronectin status. Cervicovaginal cytokine concentrations were determined by ELISA methodology. Concentrations of CRH, CRH-BP and activin-A were determined in the serum samples. Standard contingency tables with likelihood ratios, receiver operator characteristic (ROC) curve analysis, and stepwise logistic regression were used to determine the association and predictive ability of the test of interest to predict imminent delivery (delivery within 2, 7 or 10 days) or before 37 weeks. Results: One hundred and twenty one women were included in the cervical assessment and fetal fibronectin subset. Of these, preterm delivery occurred within 2, 7, 10 days and before 37 weeks in (%) 5, 12, 14 and 38. Cervical dilatation of ≥1cm had positive/negative likelihood ratios (95% CI) for delivery within 2, 7 and 10 days of 2.5 (1-6)/0.63 (0.3-1), 4.3 (2.4-7.1)/0.4 (0.2-0.8), and 5.2 (2.9-9.3)/0.3 (0.2-0.7) respectively. The positive and negative likelihood ratios (95% CI) for fetal fibronectin and the same delivery intervals were 3.3 (1.7-6.5)/0.4 (0.13-1), 4.1 (2.4-7.3)/0.4 (0.2-0.8) and 4.2 (2.4-7.4)/0.4 (0.2-0.8). Of the cervicovaginal cytokines examined, only IL-6 showed any predictive value for delivery occurring within 2, 7 or 10 days, (area under the curve =0.63, 0.75 and 0.72 respectively). The 75th centile (35pg/ml) for IL-6 had positive/negative likelihood ratios (95% CI) for delivery within 2, 7 and 10 days of 2.6 (1.2-5.8)/0.52 (0.2-1), 3.1 (1.7-5.6)/0.5 (0.2-1) and 2.9 (1.5-5.3)/0.5 (0.3-1) respectively. Logistic regression demonstrated only IL-6 to be statistically associated with delivery within 2 days (χ²=15.9; P=0.0001). IL-6, slight vaginal bleeding and cervical dilatation ≥1 cm were all associated with delivery within 7 days (χ²=23.1, 10.5, 6.4; P ≤ 0.01 [in all cases] respectively). No serum marker had any significant predictive ability for any imminent delivery interval or for delivery before 37 weeks. Combinations of the tests did not improve the predictive ability over that of cervical dilatation ≥1cm or fetal fibronectin alone. Conclusion: When predicting imminent delivery, cervical dilatation provides equivalent predictive information to fetal fibronectin and IL-6 determination. All tests, however, had limited ability in the prediction of imminent preterm delivery. Improved understanding of the mechanisms of labour and_ further development of safe sampling techniques are necessary to determine whether fetal fibronectin and cervicovaginal IL-6 have a useful role over that of cervical assessment in the prediction of imminent delivery in women with symptoms of preterm labour. |
