The role of amniotic fluid assessment in evaluating fetal well-being.

Owing to the frequent use of bedside ultrasound, much is known about the regulation of and normative values for amniotic fluid volume and the mechanisms by which this fluid is regulated. The management protocols for conditions with extremes of amniotic fluid volume have become more exact, resulting in interventions more likely to improve outcome. Much is still unclear; there are no tools to measure amniotic fluid volume with precision, and measurement of fetal urinary output is cumbersome and error-prone.