Objective: This longitudinal study was undertaken to characterize the change in the amniotic fluid volume in normal pregnancy.
Methods: Prospectively, patients with uncomplicated gestations underwent serial amniotic fluid index by a single sonographer.
Results: Fifty-six patients underwent a total of 378 determinations of amniotic fluid volume (6.8 +/- 2.5 examinations per patient). The variation in mean amniotic fluid index between 24 and 40(+6) weeks was not significantly different (p = 0.381). Among the 42 patients who delivered at term there was no significant decrease in the amniotic fluid index between their first and last measurement (p = 0.86). However, in the 14 patients who delivered after 41 weeks, there was a significant decrease in the index over time (p = 0.04).
Conclusion: The longitudinal study on amniotic fluid volume in normal pregnancy reveals that amniotic fluid index does not change significantly with gestational age.