A human embryo or fertilized ovum in the first fourteen days after fertilization, before implantation in the uterus has occurred.
- ‘Before fourteen days, the embryo, or pre-embryo as it was scientifically known, was a loose cluster of first two, then four, then sixteen cells, undifferentiated.’
- ‘Implantation of the pre-embryo in the uterine wall is a highly invasive process, akin to attack by a parasite.’
- ‘The term pre-embryo has been embraced wholeheartedly by practitioners for reasons that are political, not scientific.’
- ‘It is therefore plausible that non-barrier contraceptives may act at the level of the pre-implantation pre-embryo.’
- ‘The embryos, or pre-embryos, at fertility clinics are frozen at sometime between two and five days after fertilization.’
We take a look at several popular, though confusing, punctuation marks.