Medically reviewed by Dr. Shweta Agarwal, MBBS, DGO, Reproductive Medicine (IVF). Last updated: July 2026.
Information on this page is educational and does not replace a medical consultation. Individual clinical factors affect all outcomes.
Aansh Hospital & IVF Center is a Level-2 government-registered ART clinic serving Vidarbha and northern Telangana, with its headquarters and in-house embryology lab in Chandrapur. Lab operations — including all vitrification and cryostorage — are led by Senior Clinical Embryologist Aayush Agarwal, Ph.D. Treatment planning is led by Dr. Shweta Agarwal (MBBS, DGO, Reproductive Medicine).
भ्रूण संरक्षण (bhrun sanrakshan) — embryo freezing — is increasingly used not only for surplus IVF embryos but also for oncofertility, freeze-all cycles, and family planning. This page explains every aspect of the process clearly and without pressure.
Why would someone freeze embryos rather than transfer them immediately?
Embryo freezing is not a fallback — it is frequently the clinically preferred strategy. There are four main reasons embryos are frozen rather than transferred fresh.
1. Surplus embryos after an IVF cycle An IVF stimulation cycle typically produces more fertilised embryos than can safely be transferred in a single attempt. Freezing high-quality surplus embryos allows future FET cycles without repeating the stimulation and egg-retrieval steps — reducing physical burden, cost, and waiting time for the next attempt.
2. Freeze-all strategy for OHSS prevention In women at elevated risk of ovarian hyperstimulation syndrome (OHSS) — particularly those with PCOS or a high antral follicle count — transferring a fresh embryo on a hormonally stimulated uterus can worsen the condition. A freeze-all cycle means all embryos are frozen, OHSS is allowed to resolve, and then a single embryo transfer occurs in a stable, natural-cycle month. This significantly reduces OHSS severity without sacrificing the embryos.
3. Fertility preservation before cancer treatment (oncofertility) Chemotherapy and radiation can permanently damage ovarian function. For patients diagnosed with cancer who have a male partner (or access to donor sperm), fertilising eggs before treatment begins and freezing the resulting embryos preserves the option of a biological pregnancy after cancer treatment is complete. See our oncofertility page for the full pathway.
4. PGT timing and family planning When preimplantation genetic testing (PGT) is planned, embryos must be biopsied and frozen while results are awaited — typically 2–4 weeks. Freezing is also chosen by couples who want to bank additional embryos now, while the female partner's ovarian reserve is at its current level, for a planned second or third child in the future.
How does vitrification work — and what makes it different from older freezing methods?
Vitrification is a rapid, ultra-fast cooling process that brings embryos to −196 °C in seconds rather than minutes. The key difference from the older slow-freeze method is the prevention of ice crystals.
The problem with slow freezing: as water inside and outside embryo cells cools slowly, ice crystals form and puncture cell membranes, damaging or destroying the embryo. Slow freezing was the standard until the mid-2000s; survival rates were substantially lower.
How vitrification solves this: before freezing, embryos are placed briefly in a cryoprotectant solution that replaces much of the water in and around the cells. They are then plunged into liquid nitrogen at −196 °C so rapidly (thousands of degrees per minute) that the cryoprotectant solidifies into a glass-like (vitreous) state rather than forming crystals. No ice — no mechanical damage.
The vitrification process step by step:
- Equilibration: embryo is placed in a lower-concentration cryoprotectant bath for 5–15 minutes.
- Vitrification solution: transferred to a high-concentration cryoprotectant for 60–90 seconds.
- Loading: embryo is loaded onto a specialised carrier (e.g., Cryotop or similar device).
- Plunge: carrier is immediately submerged in liquid nitrogen — temperature drops from +37 °C to −196 °C in under a second.
- Sealing and labelling: the carrier is sealed in a uniquely labelled straw, checked by a second embryologist, and placed in a dedicated dewar (insulated tank) with continuous liquid nitrogen levels.
Embryo survival rates after vitrification and warming are consistently high at experienced centres, though outcomes vary by individual case.
Blastocyst-stage embryos (Day 5/6) are the most commonly vitrified because their inner cell mass and trophectoderm are well-defined; however, Day 3 cleavage-stage embryos can also be frozen when clinical circumstances call for it.
How long can frozen embryos be stored?
Vitrification arrests all biological activity at −196 °C. Published scientific literature includes healthy births from embryos stored for more than 20 years. There is no established upper biological limit to storage duration, provided:
- Liquid nitrogen levels in the storage dewar are continuously maintained.
- The dewar has redundant backup monitoring in place.
- Embryos are not accidentally warmed (e.g., during tank servicing — a process requiring strict protocols).
Legal and consent terms in India: the ART (Regulation) Act, 2021 specifies conditions for embryo storage, including written, informed consent from both gamete providers. Specifically, Section 28(2) of the Act limits standard embryo storage to a maximum of ten years, after which they must either be allowed to perish or, with written consent, be donated to a registered research organisation (per ART Act 2021). Longer storage (such as for oncofertility) is permitted only with prior permission from the National Board. At Aansh, all storage is governed by a written consent and storage agreement, and patients are informed well in advance of any renewal or decision point.
Practical storage timeline for most patients:
| Situation | Typical storage duration |
|---|---|
| Surplus embryo from current IVF cycle, sibling later | 2–5 years |
| Freeze-all, FET next month | Days to weeks |
| Oncofertility — awaiting cancer treatment completion | 2–10 years, sometimes longer |
| Elective embryo banking, future family | Variable — years |
If you move cities or change clinics, frozen embryos can be transported to another ART-registered facility using specialised cryo-shipping containers. This requires coordination between clinics, advance written notice, and legal paperwork.
What happens when you are ready to use your frozen embryos?
When the time comes, you will undergo a frozen embryo transfer (FET) cycle — a considerably simpler process than the original IVF cycle.
- No ovarian stimulation required. The eggs have already been retrieved and fertilised. FET involves preparing the uterine lining only — typically with oestrogen tablets or patches for 10–14 days, followed by progesterone to support implantation.
- Monitoring: 1–2 ultrasound scans confirm the uterine lining has reached an adequate thickness.
- Thawing (warming): on the morning of transfer, the embryologist warms the embryo from −196 °C to +37 °C using a controlled reverse-cryoprotectant protocol. The embryo is assessed under the microscope; only embryos that survive warming in good condition are transferred.
- Transfer: the warmed embryo is loaded into a fine soft catheter and guided into the uterine cavity under ultrasound — an outpatient procedure, usually without sedation, taking 10–15 minutes.
- Pregnancy test: a blood beta-hCG test 10–14 days after transfer.
For most patients the entire FET cycle — from starting oestrogen to the pregnancy test — takes 4–5 weeks. There is no egg retrieval, no general anaesthetic for retrieval, and no intense stimulation phase.
If you have had a failed fresh cycle and have frozen embryos remaining, an FET is very often the next recommended step.
What does embryo freezing cost?
Embryo freezing cost at Aansh has two components:
- Vitrification fee (the laboratory process of freezing the embryos) — typically included in, or charged as an add-on to, the IVF cycle cost.
- Annual storage fee — charged per year of cryostorage, covering liquid nitrogen, dewar maintenance, monitoring, and administration.
Cryostorage is charged at approximately ₹1,000 per month per straw. Final cost depends on individual clinical evaluation — see Costs & EMI for current pricing.
You receive a transparent written cost estimate before the cycle begins, covering both the vitrification and the projected storage period. 0% EMI options are available for the overall treatment package. See IVF cost & 0% EMI for a full breakdown of what is included.