Journal of Ultrasound in Medicine, Vol 12, Issue 7 383-386, Copyright © 1993 by American Institute of Ultrasound in Medicine
Pregnancy outcome after a first trimester sonogram demonstrating fetal cardiac activity
M. C. Frates, C. B. Benson and P. M. Doubilet
Department of Radiology, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts 02115.
We conducted a prospective study to assess pregnancy outcome after a first
trimester sonogram demonstrating a singleton intrauterine gestation with
fetal cardiac activity. In each of the 556 cases, data recorded included
indication for the sonogram, results of the sonogram, and pregnancy
outcome. Sonographic abnormalities were found more frequently in patients
scanned because of symptoms (14.0%) than among patients scanned for routine
indications (6.0%) (P < 0.05, chi-squared). Among 556 patients with
known outcomes, the overall loss rate was 9.4%. A trend was seen toward a
higher loss rate in patients with abnormal than normal sonograms (15.2%
versus 8.8%). The loss rate after a normal scan was similar in symptomatic
(10.6%) and asymptomatic patients (9.1%) and declined progressively with
gestational age from 17.0% at 6 to 7.9 weeks to 4.3% at 12 to 13 weeks (P
< 0.01, chi-squared). These results can be used to convey prognostic
information to patients after a normal first trimester sonogram
demonstrating fetal cardiac activity. The likelihood of a good pregnancy
outcome can be stated as a function of gestational age, and a symptomatic
patient can be reassured after a normal scan that her prognosis is similar
to that of an asymptomatic patient with a normal sonogram.