Transvaginal sonographic assessment of the cervix and preterm labor.

Objective: The purpose of the study was to assess the accuracy of cervical measurements by transvaginal ultrasonography during the 1st and 2nd trimester in the prediction of preterm labor.

Study Design: Five hundred high-risk pregnant women in preterm labor were studied retrospectively.

Results: A significantly higher percentage rate of preterm delivery was found in women with abnormal cervical length compared to those with normal cervical length (54.6% [118 of 216 women] vs 16.5% [47 of 284 women], p < 0.001). Also in women with abnormal dilatation of the internal cervical os the percentage was significantly higher compared to those with normal findings (78.7% [133 of 216 women] vs. 9.7% [32 of 284 women], p < 0.001). For women with cervical funneling the incidence of preterm delivery was significantly higher compared to the rest of the women (94.3% [33 of 35] vs 28.4% [132 of 465], p = 0.015).

Conclusion: Our data confirm that sonographic assessment between the 9th and 12th week is the best cut-off period for predicting preterm labor.