The Impact of Transvaginal Sonography in Different Positions on the Course of Labor and the Success of Induction of Labor

Objective: Aim of the multi-center study is to examine the relation between cervical length (CL) and funneling width (FW) in different positions around term and the impact on the course of labor or induction in comparison wuth the Bishop-score.

Methods: In up to now more than 120 pregnancies, TVS in both positions was performed during the last weeks of pregnancies. In addition, TVS in both positions was performed before induction of labor in more than 100 pregnancies. The Bishop score was determined by a second investigator who was blinded for TVS results. Fetal position and weight were determined by ultrasound. Data were analysed by SPSS 12.0.

Results: During the last weeks, the decrease in CL and increase in FW was more pronounced in the upright position. Funneling was more frequent in the standing position in both groups. The first stage of labor was 6.39 hours for primi- and 3.65 for multiparae . Of all parameters, funnelling in the standing position was the most significant parameter to predict vaginal delivery in comparison to secondary caesarean section after induction of labor.

Conclusions: Our previous studies have shown that TVS in the upright position (funnelling) improves the prediction of preterm birth. These new data suggest that funneling in an upright position reflects cervical ripeness around term and the success of induction better than conventional TVS or the Bishop score. This might have implications on the indication or withdrawal of priming / induction of labor and informed consent.