Doppler flow studies (duplex sonography). Differential diagnostic assessment of intrauterine growth retardation and uncertain gestational age

Abstract

In 116 patients referred to Heidelberg University Gynecological Clinic because of a discrepancy between calculated and biologically determined gestational age, the suitability of the Doppler Flow examination method (duplex method) for resolving this question was studied. The signals from the fetal descending aorta, the umbilical artery, and from maternal placental vessels were used. An A/B ratio of over 7 in the fetal aorta, an A/B ratio of over 4 in the umbilical artery, and detection of an early diastolic incisure in the so-called arcuate arteries were considered pathologic. The relatively high accuracy of this examination method is expressed by its sensitivity (91%) and likewise high specificity (86%) for this diagnostic question. In view of the predictive value of 88% thus determined, reliable differential diagnostic distinction between intrauterine growth retardation and uncertainty regarding term appears possible. Doppler sonographic examination can be performed without causing any serious discomfort to the patient and within a short period of time. While the number of false-positive results in this study was in any case relatively low (11%), an in-depth analysis showed that an "acute placental insufficiency" had occurred in the peripartum in more than one-half of the cases.