RESUMO
To compare between digital vaginal examination [DVE], transabdominal sonography [TAS] and transvaginal sonography [TVS] as regards accuracy and time requirements for determination of foetal occiput position during the second stage of labor. Prospective randomized blinded study. 120 laboring patients in the second stage of labor. An informed consent was obtained. A detailed sterile digital vaginal examination was performed immediately before transabdominal and transvaginal examinations. Each sonographer was blinded to the finding of the other as well as to the DVE finding. The findings of digital and ultrasonic examinations were compared with the actual position of the vertex, as determined by direct visualization at vaginal delivery after spontaneous restitution of the foetal head or at cesarean delivery. The foetal head position was assessed by determining the foetal occiput as "the time on a 12-hour clock" into eight categories. The findings of DVE and TAS were considered to be correct if the foetal occiput position was within +/- 45° of TVS finding. The time required by the three methods was recorded. Sensitivity, specificity and diagnostic accuracy of DVE, TAS, combined DVE and TAS and TVS [gold standard] in the determination of the foetal head positions in the second stage of labor were calculated. TVS diagnosed correctly the foetal head position in all cases [100% accuracy] when compared with the actual foetal head position at delivery and thus was considered as the gold standard. The accuracy of DVE in determining foetal head position in the second stage of labor was 72%, being higher for occiput anterior positions. DVE was inaccurate in 26.7% of cases, the majority of which were in occiput posterior positions and was unable to determine 5% of cases. The accuracy of TAS in diagnosing the foetal head position was 80.5%. TAS was inaccurate in 9.16% of cases, the majority of which were in the occiput anterior positions and was unable to determine 4.16% of cases. The accuracy of TVS was significantly higher than DVE and TAS [P= 0.001]. However, combining DVE and TAS increased the sensitivity and diagnostic accuracy than using either alone. The time required for determining foetal head position was significantly shortest for TVS in comparison to TAS or DVE [8.17 +/- 2.15 vs 29.4 +/- 2.81 or 22.27 +/- 3.59 seconds, P= 0.0001]. Transvaginal sonography is the preferred imaging method for the determination of foetal head position in the second stage of labor. However, combining DVE and TAS was more accurate in the assessment of the foetal head position than using either alone and can be used as an alternative to TVS