TRANSVAGINAL SONOGRAPHY OF THE YOLK-SAC IN NORMAL AND ABNORMAL PREGNANCY

A cross-sectional study comprising 117 consecutive first trimester sin gleton pregnancies was performed using transvaginal sonography (TVS) t o evaluate size abnormalities of the secondary yolk sac (YS) vis-a-vis pregnancy outcome. In normal pregnancy outcome (NPO) the YS diameter showed an increase from the 5th to the 11th week, menstrual age, follo wed by a decrease and its disappearance after 12 weeks. A YS of abnorm al size was statistically significant (p < 0.001) in spontaneous abort ion (SA) versus NPO, with a sensitivity of 68.7%, a specificity of 99% , a positive predictive value of 91.6% and a negative predictive value of 95.2%. These preliminary results indicate that a measurement of th e YS very early in gestation may be a useful marker of pregnancy outco me. (C) 1996 John Wiley & Sons, Inc.