Embryo Freezing vs. Egg Freezing: Differences, Data and Laws

Egg freezing and embryo freezing both preserve the chance of a future pregnancy, and both start with the same IVF steps. The difference is what gets frozen: unfertilized eggs, or eggs that have already been fertilized with sperm. This guide explains the practical differences, shows how common freezing is in US clinic data, and summarizes how some fertility destinations regulate it. It is general information, not medical advice.

What each one is

The CDC defines cryopreservation as freezing eggs or embryos from an ART cycle for potential future use.^[2] It defines an egg or embryo banking cycle as an ART cycle started with the intent of freezing all resulting eggs or embryos, and notes that long-term banking is also called fertility preservation.^[2]

• Egg freezing: eggs are retrieved and frozen unfertilized.
• Embryo freezing: retrieved eggs are fertilized in the lab with sperm from a partner or donor, grown for several days, and the resulting embryos are frozen.^[3]

Both require ovarian stimulation with fertility medicines and an egg retrieval procedure, as described by MedlinePlus.^[3]

Key differences

	Egg freezing	Embryo freezing
Sperm source needed now?	No	Yes (partner or donor)
Fertilization	Later, after thawing	Before freezing
Information at freezing	Number of eggs	Number of embryos that developed; embryos can be genetically tested before freezing
Future decisions	Belong to the person who froze the eggs	Usually shared by both people who created the embryos

The last row matters. Embryos created with a partner usually involve joint decisions about use, storage and disposal, and those agreements can become difficult if a relationship ends. Laws differ by country, as the examples below show.

How common is freezing in the US?

In 2022, 9.2% of all ART cycles in the US were fertility-preservation cycles.^[1] The share varies by age:

Age group	Share of cycles for fertility preservation (2022)
Under 35	10.5%
35–37	11.5%
38–40	8.6%
Over 40	4.7%

The CDC’s fertility-preservation figure does not separate egg freezing from embryo freezing.^[1] Clinics also list egg or embryo banking as a reason for treatment in 43% of cases in 2022, the most common reason reported.^[1]

Freezing is also central to routine IVF. In 2022, 86.9% of US embryo transfers used frozen embryos.^[1] See frozen vs. fresh embryo transfer.

How many clinics offer each?

Among US clinics with 2022 data, 449 of 451 report offering egg cryopreservation and 451 of 451 report offering embryo cryopreservation.^[1] In other words, nearly every reporting IVF clinic offers both. Use the filters on any state page to see which clinics offer egg freezing near you.

Using frozen eggs or embryos later

Frozen eggs must be thawed and then fertilized in the lab, often using ICSI, before an embryo can be transferred, so using them involves the remaining IVF steps.^[3] Frozen embryos skip that stage: they are thawed and transferred, usually in a planned cycle. Either way, the person who will carry the pregnancy is prepared for transfer.

Donating unused embryos

Some people end up with embryos they will not use. Options typically include continued storage, donation to research where permitted, donation to another patient, or disposal. Among US clinics with 2022 data, 275 of 451 report offering donated embryo services.^[1] Nationally, 42.2% of transfers using donated embryos resulted in a live birth in 2022.^[1] See donor egg and donated embryo success rates.

Age and egg freezing

MedlinePlus notes that a woman is most fertile in her early 20s, that the chance of pregnancy begins to decrease around age 35, and that early egg retrieval and storage is an option for women who know they will delay childbearing, while also describing it as expensive.^[7] See egg freezing in the US for state-by-state data.

How other countries regulate it

Rules on freezing, storage and use vary widely. Some examples from our destination guides:

• Spain: the national registry reports that 65,805 eggs were vitrified for fertility preservation in 2023, up from 58,248 in 2022, and 1,284 embryo transfers used eggs from patients who had preserved their fertility.^[4] See Spain.
• Greece: Law 4958/2022 explicitly allows freezing eggs and embryos for social reasons, removed the former 20-year limit on storage, and lets a person store unfertilized eggs or sperm without a spouse’s or partner’s consent.^[5] See Greece.
• Czech Republic: Act 373/2011 requires the clinic to contact the couple about continued storage or disposal of unused embryos after 10 years.^[6] See Czech Republic.

Questions to ask a clinic

• How many eggs or embryos does the clinic typically retrieve or create for someone my age?
• What are the clinic’s own results with thawed eggs and with frozen embryo transfers?
• What are the yearly storage fees, and what happens if they go unpaid?
• Can frozen eggs or embryos be moved to another clinic or another country?
• For embryos: what consent forms decide what happens to them if we separate, or if one of us dies?

Related guides

• Egg freezing in the US
• Frozen vs. fresh embryo transfer
• PGT: how often US clinics use it
• What is infertility?