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Objective: The aim of this study was to determine the value of a gray-level histogram of the uterine cervix as a predictor of preterm birth (PTB) in asymptomatic pregnant gravidas.
Methods: One hundred and one asymptomatic gravidas at 15-28 weeks gestation were enrolled in this prospective study. A transvaginal ultrasonography for measurement of cervical length (CL) and gray-scale histogram was performed as part of a routine antenatal examination. Anterior and posterior cervical walls and AP difference in MGL (mean gray level between anterior and posterior) were checked. And we analyzed the relationship between the values and PTB. PTB at ＜37 weeks gestation were recorded.
Results: The overall rate of PTB was 15.8% (16/101). Logistic regression analysis demonstrated that not only cervical length (odds ratio [OR], 0.92; 95% confidence interval [CI], 0.87-0.98, p = 0.007), but also AP difference in MGL (OR, 0.82; 95% CI, 0.74-0.91, p = 0.001) was independent predictor of preterm birth. A combined approach in which a gravida was regarded as positive with a short cervical length (≤ 26 mm) and AP difference in MGL (≤ 13.3) had a sensitivity of 68.8% for preterm birth. Shortened cervical length (≤ 26 mm) and reduced AP difference in MGL (≤ 13.3) compared with normal cervical length and AP difference in MGL had an 11.42-fold (95% CI, 1.59-82.32) increased the risk of PTB.
Conclusion: Gray-level histogram of the uterine cervix may predict the preterm birth in asymptomatic pregnant gravidas.