Glossary · Definition · v2026.3
What Is Embryo Compaction?
Embryo compaction is the developmental process in which individual blastomeres tighten their cell-to-cell junctions and merge into a compact mass, forming a morula. This is a critical step before blastocyst formation.
Clinical significance
Compaction is a key developmental checkpoint. Embryos that fail to compact typically do not progress to the blastocyst stage. The timing and completeness of compaction are assessed by embryologists using time-lapse imaging.
Common confusion
Compaction is sometimes mistaken for the blastocyst stage itself. Compaction precedes cavitation (fluid accumulation) and is a prerequisite for blastocyst formation.
Related reference
Used in
This content defines terminology for educational orientation. It does not constitute medical advice.
IVF Daddies Newsletter
Structural briefings on policy, clinical, and regulatory developments.
Weekly updates on family-building governance.