Sonographic estimation of amniotic fluid volume. Subjective assessment versus pocket measurements.

Amniotic fluid volume (AFV) estimation is an important part of routine obstetric sonography. Despite the clinical importance placed upon excessive or diminished AFV in pregnancy, there is little uniformity in the way it is estimated sonographically. We compared AFV estimations obtained using two commonly employed sonographic methods "subjective" visual assessment and amniotic fluid pocket measurements. Estimates obtained using both methods correlated closely. In addition, there was excellent intraobserver and interobserver agreement among estimates obtained using subjective criteria. This supports the belief that experienced observers tend to agree on the sonographic appearance of normal, excessive or decreased AFV. Methods for AFV estimation and potential pitfalls are discussed.