Pregnancy outcome after a first trimester sonogram demonstrating fetal cardiac activity

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.