Glossary · Definition · v2026.3
What Is an Embryo?
An embryo is the earliest stage of human development that forms after an egg is fertilized by sperm.
How an Embryo Forms
Once fertilization occurs, the egg begins dividing into multiple cells. During the first several days, the embryo continues to grow and organize into more complex structures. In IVF treatment, embryos are usually grown in a laboratory for several days before they are transferred to the uterus or frozen for future use.
Why It Matters in IVF
The goal of IVF is to create healthy embryos that can implant in the uterus and develop into a pregnancy. Not all fertilized eggs will develop into viable embryos. This natural attrition is expected and reflects the biological reality of early human development.
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This content defines terminology for educational orientation. It does not constitute medical advice.
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