The effect of maternal blood contamination on amniotic fluid glucose and white blood cell count from preterm gestations.

Abstract

To determine the influence of maternal blood contamination on amniotic fluid (AF) glucose and white blood cell count (WBC). Amniotic fluid from 23 preterm, nondiabetic pregnant women was studied. Maternal blood was added to the AF at increasing concentrations, and glucose and WBCs were assessed. The median AF glucose in the uncontaminated specimen was 43 mg/dL (range 11-86). Median glucose levels were unchanged by the addition of maternal blood until a mean +/- standard deviation AF red blood cell count of 63,000 +/- 22,000/mm3 was exceeded, at which time the median glucose level significantly increased to a median of 45 mg/dL (range 19-90). The ratio of observed to expected values of WBCs ranged from 0.12-1.8, regardless of the level of maternal blood contamination. Glucose levels in preterm AF-containing maternal blood are accurate in all except the most heavily contaminated specimens. Accurate determination of the WBC in contaminated AF is difficult.