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Abstract

Ultrasound evaluation is widely accepted as an accurate tool in the assessment of the fetal head during labor. Several classification systems have been proposed to aid in the assignment of different fetal head positions. In 1998 Gardberg et al.1 classified fetal head position as occipitoanterior and occipitoposterior. In 2002, Sherer et al.2 classified it as occiput anterior (OA), occiput posterior (OP), left or right occiput transverse (LOT and ROT) and left or right occiput anterior or posterior (LOA, ROA, LOP and ROP). In the same year, Akmal et al.3 proposed recording the fetal head position according to a clock-like diagram with 24 divisions. Similar clocks, with 24, 12 and eight divisions were used by Rane et al.4, Zahalka et al.5 and Dupuis et al.6, respectively. Using one of these classification methods should enable the clinician to discern promptly the position of the fetal head in most cases, although any clinician would find it very difficult to analyze the fetal head when it lies in a position of transition (e.g. between OP and OT). Attempts have been made to address these borderline situations by modifying the number of clock subdivisions or, in cases when the fetal head position did not match one of the defined grid lines, the nearest location was given, but we and others3, 6 have been unable to solve the issue as the object of analysis is not punctiform. In our opinion, Drs Eggebo and Salvesen, in their Correspondence, do not help solve, improve or modify the current definition of fetal head position. Their main concern is the division of the Akmal clock and the fact that, in our study, the borderline limits were 02 : 29, 03 : 29, 08 : 29 and 09 : 29 hours instead of the 02 : 30, 03 : 30, 08 : 30 and 09 : 30 hours used by Akmal et al.3. Because the fetal head is not punctiform it appears that the difference in the two models is actually irrelevant in the overall assessment. For the purposes of our study7, the position of the fetal head was allocated within the portion of the clock in which the largest part of the fetal occiput was visualized and, in the Methods section, we clearly state that the clock was divided into 12 sections and not into 720 sections as implied by Drs Eggebo and Salvesen. We acknowledge that it would not be useful to try to differentiate the position of the occiput between, for example, a 02.29 and 02.30-hours position and are aware that it would be equally unhelpful to have the same position of 02.30 hours identifying two different positions. The modifications of the Akmal clock made in our paper were not an attempt to solve the issue of borderline cases, merely representing an interpretation that we believe had no effect on the overall analysis. Regarding the relevance of assessment of fetal head position before and in the first stage of labor, considering the findings of Peregrine et al.8, Akmal et al.9 and Souka et al.10, that the position before and in the first stage of labor is not predictive of fetal head at delivery, the data on which our discussion was focused were position at the second stage of labor. In closing, we recognize the importance of keeping alive the discussion on fetal occiput position in borderline cases, but are not convinced that the criticisms of our study contribute helpfully to the debate. I. Blasi*, V. Vinci*, W. Henrich*, V. Mazza*, * Arcispedale Santa Maria Nuova, Modena and Reggio Emilia University, Reggio Emilia, Italy