abnormal blastocyst formation
DEF: atypical formation of a blastocyst from a solid ball of cells known as a morula, including anomalies in the formation of a fluid-filled cavity (blastocoele) and/or initiation of inner cell mass and trophectoderm differentiation.
failure of blastocyst formation
DEF: inability to form a blastocyst from a solid ball of cells known as a morula
SYN: absent blastocyst
NOTE: existing term "failure to form blastocele [MP:0002663]" should be made a child of “failure of blastocyst formation”