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 fetalheart 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 reviewedfor yolk sac information. The TVU was performed between 5 and 6 weeksfollowing presumed conception (heart motion data) and between 22 and 32days following in-vitro fertilization (yolk sac data). Pregnancies werefollowed until an ongoing pregnancy or spontaneous abortion was documented.The presence of a yolk sac between 22 and 32 days from fertilization wasassociated with the development of fetal heart motion in 94% of cases. Theabsence of the yolk sac by 32 days after fertilization was alwaysassociated with a poor outcome. In women < 36 years of age, the presenceof fetal heart motion was associated with a spontaneous abortion in only4.5% of the cases. However, the incidence of spontaneous abortion followingfetal 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 beconsidered a reassuring sign in the older woman. These data haveimplications regarding early embryology and the counselling of infertilitypatients.