Egg Freezing (Oocyte Cryopreservation)
Egg freezing is a procedure in which mature eggs retrieved from the ovaries are vitrified (flash-frozen at −196°C) and stored for future IVF. The American Society for Reproductive Medicine (ASRM) removed the experimental designation from oocyte cryopreservation in 2012. Live birth rates are age-dependent at the time of egg retrieval: ~49% for patients under 35, declining to 32.5% at ages 38–40 and 20% at ages 41–42.
What Egg Freezing Is — Entity Attributes
| Medical term | Oocyte cryopreservation (planned or medically indicated) |
| ASRM status | Standard of care since 2012 (experimental label removed) |
| Freezing method | Vitrification — ultra-rapid cooling (23,000°C/min) in liquid nitrogen at −196°C |
| Prior method (obsolete) | Slow-freeze — replaced by vitrification ~2010 due to lower survival rates |
| Storage duration | Eggs remain viable indefinitely in liquid nitrogen |
| Success rate — frozen under 35 | ~49% live birth rate per thaw cycle (research data) |
| Success rate — frozen at 38–40 | ~32.5% per thaw cycle |
| Success rate — frozen at 41–42 | ~20% per thaw cycle |
| Critical variable | Age at egg retrieval — not age at transfer |
| Post-thaw survival (vitrification) | >90% in experienced laboratories |
The Egg Freezing Process — 4 Stages
The egg retrieval phase is identical to IVF. The difference is that eggs are vitrified rather than immediately fertilized. Future use requires a separate thaw-and-fertilization cycle.
Ovarian Stimulation
Injectable gonadotropins (FSH and LH) are administered daily for 8–14 days to stimulate multiple follicle development — unlike the single follicle of a natural cycle. Response is monitored by serial transvaginal ultrasound and serum estradiol. Stimulation ends when lead follicles reach 17–20mm. An hCG or GnRH agonist trigger is given.
Egg Retrieval
36–38 hours post-trigger, eggs are retrieved via transvaginal ultrasound-guided needle aspiration under intravenous sedation. The embryologist assesses each egg for maturity immediately post-retrieval. Only mature (MII) oocytes are suitable for vitrification. Immature eggs are not frozen in standard clinical practice.
Vitrification
Mature eggs are exposed to cryoprotectant solutions and plunged into liquid nitrogen within minutes of retrieval. Vitrification at 23,000°C per minute prevents ice crystal formation inside the egg — the primary cause of cellular damage in older slow-freeze protocols. Survival rates post-thaw exceed 90% in experienced laboratories using vitrification.
Future Thaw and IVF Cycle
When the patient returns to use frozen eggs, a frozen embryo preparation cycle begins. Eggs are warmed, assessed for survival, and fertilized via ICSI. Resulting embryos develop to blastocyst stage. One embryo is transferred to the uterus. Outcome depends on number of eggs stored, age at freezing, and uterine receptivity at time of transfer.
Egg Freezing Success Rates
Why Age at Freezing Is the Critical Variable
Egg quality declines with age due to increasing chromosomal aneuploidy (abnormal chromosome number). This occurs in the egg, not the uterus. A 44-year-old patient transferring an embryo created from eggs frozen at age 31 achieves success rates comparable to a 31-year-old — because the egg's biological age determines the outcome, not the uterus's age.
Live Birth Rate by Age at Egg Freezing
| Under 35 | ~49% live birth rate per thaw cycle |
| 35–37 | Intermediate decline below under-35 cohort |
| 38–40 | ~32.5% per thaw cycle |
| 41–42 | ~20% per thaw cycle |
| Over 42 | Substantially lower; donor eggs typically recommended |
Source: ASRM Congress research; peer-reviewed REI literature. The CDC NASS reports frozen embryo transfer outcomes within clinic profiles but does not publish a standalone national egg freezing success rate.
Number of Eggs and Success Probability
Live birth probability increases with the number of mature eggs stored. Research indicates 10–15 mature eggs retrieved before age 35 provides a reasonable bank for one live birth attempt. A reproductive endocrinologist estimates expected egg yield based on antral follicle count (AFC) and anti-Müllerian hormone (AMH) before commencing a retrieval cycle.
Egg Freezing Cost in the United States
| Egg retrieval cycle (monitoring + retrieval) | $10,000–$20,000 |
| Gonadotropin medications | $3,000–$6,000 per retrieval |
| Annual egg storage | $500–$1,000 per year |
| Future thaw and IVF cycle | $4,000–$8,000 (excludes medications) |
| Insurance coverage — elective | Rarely covered by standard plans |
| Insurance coverage — medical indication | Oncofertility (pre-cancer treatment) more often covered |
Egg Freezing vs Embryo Freezing
| What is frozen | Egg freezing: unfertilized oocyte / Embryo freezing: fertilized embryo (blastocyst) |
| Partner sperm at time of freezing | Egg freezing: not required / Embryo freezing: required |
| PGT-A possible before freeze | Egg freezing: No (PGT requires an embryo) / Embryo freezing: Yes |
| Legal ownership | Egg freezing: sole ownership / Embryo: both partners (complex if relationship changes) |
| Post-thaw survival | Both: >90% with vitrification in experienced laboratories |
| Typical recommendation | Egg freezing: single patients / Embryo freezing: partnered patients with known sperm source |
Find Egg Freezing Clinics by City
The clinics in this directory offer egg freezing alongside IVF services.