morula

Full Definition

A developmental stage of the early embryo that occurs approximately 4 days after fertilization, characterized by a solid ball of 16-32 cells with no internal cavity. The morula represents an intermediate stage between the cleavage-stage embryo and the blastocyst. In IVF laboratories, embryos at the morula stage may be cultured further to blastocyst stage for transfer, or may be cryopreserved for future use, though blastocyst transfer is generally preferred when possible.

Usage

Usage note: Latin term meaning 'little mulberry' due to its appearance.

In Context

• "Two embryos developed to morula stage by day 4 of culture." — Laboratory report
• "The morula showed signs of early compaction." — Embryology assessment