Early transvaginal ultrasound following an accurately dated pregnancy: the importance of finding a yolk sac or fetal heart motion.

Our goals were to determine the prognostic value of a yolk sac or fetal heart motion seen during an early accurately dated transvaginal ultrasound (TVU). We reviewed 225 consecutive pregnancies for fetal heart motion data. Furthermore, 63 pregnancies following in-vitro fertilization were reviewed for yolk sac information. The TVU was performed between 5 and 6 weeks following presumed conception (heart motion data) and between 22 and 32 days following in-vitro fertilization (yolk sac data). Pregnancies were followed until an ongoing pregnancy or spontaneous abortion was documented. The presence of a yolk sac between 22 and 32 days from fertilization was associated with the development of fetal heart motion in 94% of cases. The absence of the yolk sac by 32 days after fertilization was always associated with a poor outcome. In women < 36 years of age, the presence of fetal heart motion was associated with a spontaneous abortion in only 4.5% of the cases. However, the incidence of spontaneous abortion following fetal heart motion increased to 10% in women 36-39 years and 29% in women > or = 40 years of age. The presence of heart motion should not be considered a reassuring sign in the older woman. These data have implications regarding early embryology and the counselling of infertility patients.