How frequently should the amniotic fluid index be performed during the course of antepartum testing?
OBJECTIVE: Our purpose was to evaluate the need for frequent amniotic fluid volume assessments in our antepartum testing unit. STUDY DESIGN: In a retrospective analysis of data accumulated over 1 year in our antepartum testing unit amniotic fluid index values performed at 3- to 4-day intervals were compared with follow-up values. Of 11,827 amniotic fluid index values, there were 6291 with follow-up values within 4 days. The results were stratified on the basis of the subsequent amniotic fluid index value and estimated gestational age. Comparisons were made relating to amniotic fluid index testing intervals of 4 versus 7 days. RESULTS: Patients with an amniotic fluid index > 8 cm had a 2.3% chance (128/5677) of having oligohydramnios (amniotic fluid index < or = 5.0 cm) in the next 4 days. Those patients with low-normal amniotic fluid index values (5 to 8 cm) had a 16.2% chance (96/593) of having oligohydramnios in the next 4 days. There were few patients with an amniotic fluid index <
