Accuracy of real-time sonography in the determination of fetal viability.

After 8 weeks of fetal age, real-time ultrasonography is a simple, rapid, and highly reliable technic for differentiating a viable from a dead fetus. Fetal movements are invariably detected after 8 weeks of fetal life, and a discrete, fluid-filled, intrathoracic pulsating heart can be seen after 11-12 weeks of fetal life. Absence of these findings, as observed by two independent examiners each viewing the fetus for 3 minutes with real-time sonography, provides reliable evidence of fetal demise. A prospective evaluation of 390 consecutive fetuses yielded only one false positive diagnosis of fetal viability. No living fetus was diagnosed as being dead.