In some very rare instances, the blastocyst will attach itself not to the uterine wall but to the inside of the Fallopian tube or some other place outside the uterus, i.e., in the abdominal cavity.

• 在一些非常罕见的例子，胚泡不是附着在子宫壁，而是附着在输卵管内壁或子宫之外的一些其他部位（例如腹膜腔）。