title: Does the amniotic fluid index change over a short-term time interval?
abstract: The amniotic fluid index (AFI) is a rapid and simple technique that is commonly used to assess amniotic fluid volume. It is commonly used in conjunction with other tests of fetal well-being that extend over a variable time interval. The data on interobserver and intraobserver variability have not stated the interval between measurements, although it is likely that they have been repeated immediately. In this study an AFI was repeated after a short time interval to assess whether a significant difference exists, as this may be clinically relevant. In 91 patients, the AFI was performed at the beginning and end of an ultrasound scan for either growth and development, or for Doppler velocimetry. The interval between the two measurements was 30-45 min, and the respective results were as follows: mean 18.4 vs. 18.7; standard deviation 4.2 vs. 3.9; minimum value 10.1 vs. 11.0 and maximum value 35.0 vs. 30.0. There were no significant differences between the two measurements (p > 0.133; d.f. = 90) and the correlation coefficient was 0.874 (p < 0.0001). These results validate the reproducibility of the AFI over a 30-45 min interval, during which time most adjunctive tests are usually completed. Therefore, the timing of the AFI in relation to the other tests is not critical.
authors.affiliation: Sinai Hospital, Wayne State University, Detroit, Michigan 48235, USA.
authors.forename: D B
authors.initials: DB
authors.lastname: Schwartz
authors.forename: Y
authors.initials: Y
authors.lastname: Daoud
authors.forename: K
authors.initials: K
authors.lastname: Schuchter
authors.forename: J
authors.initials: J
authors.lastname: Freeman
authors.forename: K
authors.initials: K
authors.lastname: McGirr
authors.forename: S
authors.initials: S
authors.lastname: Campbell