Journal of Ultrasound in Medicine, Vol 17, Issue 12 765-768, Copyright © 1998 by American Institute of Ultrasound in Medicine
Frequency and nature of structural anomalies in fetuses with single umbilical arteries
J. S. Chow, C. B. Benson and P. M. Doubilet
Department of Radiology, Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
Published studies differ concerning the rate of anomalies occurring in the
presence of a single umbilical artery and the significance of the single
umbilical artery as an isolated sonographic finding. We assessed the
frequency, nature, and sonographic detection of structural anomalies in
fetuses with a single umbilical artery. We identified all cases in which
prenatal sonography diagnosed a single umbilical artery. Cases were
excluded if postnatal physical or pathologic examination demonstrated a
three-vessel cord, yielding a study population of 167 cases. For each case,
we recorded the gestational age at diagnosis of single umbilical artery and
the findings of the sonographic fetal anatomic survey. We recorded
postnatal clinical and pathologic information when available. Gestational
age at time of diagnosis ranged from 16.8 to 41.1 weeks (mean, 29.2 +/- 6.5
weeks). Twenty of the 167 fetuses (12%) were twins, and the remainder were
singletons. Among 118 cases with postnatal information, 37 (31%) had
structural abnormalities, often involving multiple organs. The most common
organ systems involved were the heart (19 cases) and the gastrointestinal
(14 cases) and central nervous systems (nine cases). Five of the anomalous
fetuses had abnormal karyotypes. The sonographic survey was abnormal in 31
of the 37 anomalous fetuses (84%). Among 85 cases with apparently isolated
single umbilical artery at sonography and known fetal outcome, six (7%)
proved to be anomalous at birth. We had two sonographic false-positive
results (mild hydronephrosis, suspected skeletal dysplasia). In summary,
approximately one third of fetuses with single umbilical artery have
structural anomalies, most often cardiac. Even when the single umbilical
artery is an apparently isolated sonographic finding, the likelihood that
the neonate will prove to have structural anomalies is considerable (7% in
our series).
