Effect of fetal movement on the amniotic fluid index.
OBJECTIVE
Fetal movement has been shown to change the size and location of amniotic fluid pockets during measurement of the amniotic fluid index. The effect of redistributing the fixed intrauterine fluid volume on the amniotic fluid index is unknown. Therefore we tested the hypothesis that the amniotic fluid index was unaffected by fetal movement.


METHODS
A single examiner prospectively determined the amniotic fluid index before and after three discrete episodes of fetal movement during 96 biophysical profiles. A reliable blinded examiner provided a second postmovement measurement as a control. Data were analyzed by the paired t test.


RESULTS
The mean change in the amniotic fluid index after fetal movement was 1.5 +/- 0.1 cm and 2.5 +/- 0.2 cm for postmovement determinations by the same examiner and blinded observer, respectively (p < 0.001).


CONCLUSIONS
Interobserver and intraobserver variation can account for the change in the amniotic fluid index after fetal movement.
Wax
J R
JR
Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Costigan
K
K
Callan
N A
NA
Gegor
C
C
Johnson
T R
TR
D000653:Amniotic Fluid / Q000502:physiology*; D005324:Fetal Movement / Q000502:physiology*; D006801:Humans; D015588:Observer Variation; D011446:Prospective Studies; D016037:Single-Blind Method