title: Distinguishing normal from abnormal gestational sac growth in early pregnancy.
abstract: In order to evaluate normal and abnormal gestational sac development, serial sonograms were performed in 83 women whose initial sonogram demonstrated a gestational sac lacking a detectable embryo. Of 53 normal gestations, the mean sac growth was 1.13 mm/day (range, 0.71-1.75). In comparison, of 30 abnormal gestations, 24 demonstrated sac growth, and of these, the mean growth was 0.70 mm/day (range, 0.14-1.71). Based on these observations, we suggest that gestational sac growth of less than or equal to 0.6 mm/day is evidence for abnormal development. Analysis of the initial and follow-up scans for the 53 normal gestations showed that a living embryo was always detected when the mean gestational sac was greater than 25 mm in average diameter, and a yolk sac was always seen when the mean sac diameter was greater than 20 mm. In comparison, of 30 abnormal gestations, six were greater than 25 mm without a detectable embryo, and four were greater than 20 mm without a yolk sac. Recommendations for the optimal time of a follow-up sonogram are presented based on the initial sac size.
mesh_terms: D020964:Embryo Loss / Q000175:diagnosis*; D005260:Female; D005313:Fetal Death / Q000175:diagnosis*; D006801:Humans; D011247:Pregnancy; D011248:Pregnancy Complications / Q000175:diagnosis*; D013997:Time Factors; D014463:Ultrasonography; D015017:Yolk Sac