Purpose: to demonstrate the interobserver variation existing in the ultrasonographic measurement of amniotic fluid index (AFI) and in the measurement of pocket area, and to compare these two methods. In addition, an attempt was made to establish the intraobserver variation in the measurement of this index. Methods: values of AFI, described by Phelan et al.18, were studied in a group of 80 pregnant women considered to be clinically normal, seen at the Ultrasonography and Medical Updating School of Ribeirão Preto and in the Department of Gynecology and Obstetrics of the Faculty of Medicine of Ribeirão Preto, University of São Paulo (FMRP-USP). All pregnant women had a gestational age of more than 24 weeks. Fifty of these patients were submitted to AFI evaluation by 5 different ultrasonographists using the same equipment and during the same period of time, in order to determine the interobserver variation of this index. In addition, planimetric measurement of the area was performed by 2 of these 5 ultrasonographists, selected at random, in an attempt to determine interobserver variation in area measurement. Another group of 30 pregnant women was evaluated by the same ultrasonographist in an attempt to evaluate intraobserver variation in terms of AFI measurement. Results: There was a significant interobserver variation in AFI measurement and a significant variation in area measurement. However, the intraobserver variation in AFI measurement was nonsignificant. There was a correlation between AFI and area measurements. Conclusions: we emphasize the obstetrical applicability of this index and the easier execution of this method compared to area measurement, despite the importance of both procedures.
Amniotic fluid; Ultrasonography; Fetus
