A Maternal Walking Test for the Evaluation of Fetal Well-Being

Abstract

Maternal exercise is a simple and convenient way of inducing maternal cardiovascular stress. This report describes a technique for assessing fetal well-being during maternal ambulation using a newly developed multidirectional beltless ultrasound transducer system and a beltless tocotransducer. Fetal heart rate (FHR) pattern during and after a brief period of maternal ambulation was examined for presence of fetal tachycardia with loss of FHR variability or late decelerations. Maternal walking test, nonstress test, and biophysical profile results from 85 patients were compared using the FHR pattern observed in early labor as the end-point. Of the 13 patients with abnormal walking tests, 9 had abnormal early labor FHR pattern, while only 1 of the 72 patients with normal walking tests were abnormal in early labor (sensitivity = 90% (P < 0.05), specificity = 94.6%, positive predictive value (PPV) = 69%, negative predictive value (NPV) = 98.6%). By contrast, the NST detected 5 nonreactive fetuses, 4 of which showed abnormal FHR pattern in early labor; 6 of 80 reactive NST cases developed abnormal early labor FHR (sensitivity = 40%; specificity = 98.6%; PPV = 80%, NPV = 92.5%). The biophysical profile was much less sensitive than either tests: Only 1 fetus received a low score (=s6). Maternal ambulation enhances the sensitivity of antepartum FHR testing when compared to resting NST, with a reasonable false-positive rate (3 1%).

Key Words:

• Fetal heart rate
• Fetal monitoring
• Maternal exercise
• Antepartum fetal testing