Fetal Head Position during the First Stage of Labor: Comparison between Vaginal Examination and Transabdominal Ultrasound.

Abstract

Introduction. Recent evidence indicates that clinical examination, for determination of fetal head position, is subjective and inaccurate. Present study was aimed to compare transabdominal ultrasound for fetal head position with vaginal examination during first stage of labor. Material and Methods. This prospective study was performed at a tertiary center during a two-year period. Before or after clinically indicated vaginal examinations, transverse suprapubic transabdominal real-time ultrasound fetal head position assessment was done. Frequencies of various ultrasound depicted fetal head positions were compared with position determined at vaginal examination. Results. In only 31.5% of patients, fetal head position determinations by vaginal examinations were consistent with those obtained by ultrasound. Cohen's Kappa test of concordance indicated a poor concordance of 0.15. Accuracy of vaginal examination increased to 66% when fetal head position at vaginal examination was recorded correct if reported within +45° of the ultrasound assessment. Rate of agreement between the two assessment methods for consultants versus residents was 36% and 26%, respectively (P = 0.17). Conclusion. We found that vaginal examination was associated with a high error rate in fetal head position determination. Data supports the idea that intrapartum transabdominal ultrasound enhances correct determination of fetal head position during first stage of labor.