Five‐Millimeter and Smaller Embryos Without Embryonic Cardiac Activity

Objective. The purpose of this study was to assess outcomes in embryos with a crown‐rump length (CRL) of 5 mm or less without embryonic cardiac activity (ECA) among pregnant women with vaginal bleeding in the first trimester. Methods. A retrospective study of all first‐trimester sonograms in women with vaginal bleeding from 1999 to 2002 was conducted. Results. Thirty‐seven embryos without detectable ECA that had a CRL of 5 mm or less were identified. All resulted in pregnancy failure. The breakdown of these embryos by CRL was as follows: 13 were 5 mm; 10 ranged from 4 to 4.9 mm; 11 ranged from 3 to 3.9 mm; and 3 ranged from 2 to 2.9 mm. Conclusions. In pregnant women with vaginal bleeding, embryos of 5 mm and smaller without a heartbeat all resulted in pregnancy failure.