Impact of ultrasound guided training in the diagnosis of the fetal head position during labor: A prospective observational study.

OBJECTIVES:To assess whether the additional training with transabdominal ultrasound may improve the accuracy of the transvaginal digital examination in the assessment of the fetal head position during the active stage of labor. METHODS:Prospective observational study involving 2 residents in their 1 st year of training in Obstetrics with no prior experience in neither transvaginal digital examination nor ultrasound. Women with term, cephalic presenting fetus and active labor with cervical dilation ≥ 8 cm and ruptured membranes were included. In the preliminary phase of the study, the resident A ("blinded") was assigned to assess the fetal head position by transvaginal digital examination, while the resident B ("unmasked") performed transvaginal digital examination following transabdominal ultrasound, which was considered to be the gold standard to determine the fetal head position. After 50 examinations independently performed by each resident in the training phase, a post-training phase of the study was carried out to compare the accuracy of each resident in the diagnosis of fetal head position by digital assessment. The occiput position was eventually confirmed by ultrasound performed by the main investigator. RESULTS:Over a 6 months period, 90 post-training vaginal examinations were performed by each resident. The number of incorrect diagnoses of head position was higher for the "blinded" resident compared with the "unmasked" resident subjected to the ultrasound training (28/90 or 31.1 % vs 15/90 or 16.7 % p = 0.02). For both residents a wrong diagnosis was more likely with non-OA vs OA fetuses but this difference was statistically significant for the "blinded" Resident (10/20 or 50 % vs 18/70 or 25.7 % p = 0.039) but not for the "unmasked" Resident (5/18 or 27.9 % vs 10/72 or 13.9 % p = 0.16). CONCLUSION:The addition of transabdominal ultrasound as a training tool in the determination of the fetal head position during labor seems to improve the accuracy of the transvaginal digital examination in unexperienced residents.