Frozen Embryo Transfer (FET): Success Rates, Timeline & Complete Guide

For many couples going through IVF, reaching the stage where embryos are frozen and ready for transfer is both exciting and nerve-wracking. Frozen Embryo Transfer (FET) has become one of the most common fertility treatments worldwide. Thanks to advances in embryo freezing techniques (vitrification), success rates have improved dramatically, making FET an excellent option for many patients.

If you’re preparing for your own transfer, you might wonder: What happens during an FET? How successful is it? How should I prepare?

This comprehensive guide answers all those questions. We’ll walk you through what FET is, how it works, the types of cycles, success factors, timeline, preparation, and even what happens if it doesn’t work. By the end, you’ll feel better informed and more confident about your fertility journey.

What is Frozen Embryo Transfer (FET)?

Frozen embryo transfer is a procedure where embryos created during an IVF cycle are cryopreserved and later thawed for transfer into the uterus. This “pause” in the fertility process allows the body time to recover, making the uterine environment more receptive.

How it works:

• During IVF, multiple embryos are created.

• One or two may be transferred immediately (fresh transfer).

• The rest are frozen using vitrification, a flash-freezing method that prevents ice crystals from damaging cells.

• These embryos can be stored safely for years and used later when the time is right.

Fresh vs Frozen Embryo Transfer

Why do many couples prefer FET:

• Allows for better uterine lining preparation

• Offers flexibility in timing

• Provides opportunities for genetic testing

• Higher success rates in many cases

Types of FET Cycles

1. Natural FET Cycle

Uses your body’s natural ovulation. Best suited for women with regular cycles.

Pros:

• Minimal medication

• More natural hormone balance

• Lower cost

Cons:

• Requires precise monitoring

• Less flexibility in timing

• Higher risk of cancellation if ovulation isn’t predictable

2. Medicated FET Cycle

Uses estrogen and progesterone to control the cycle. Suitable for women with irregular periods, thin uterine lining, or when timing needs to be controlled.

Pros:

• Greater control over timing

• More predictable outcomes

• Recommended for many fertility patients

Cons:

• Requires hormone medication

• May cause mild side effects (mood changes, fatigue, breast tenderness)

Read more: Infertility Solutions: Medical & Lifestyle Treatments That Help

FET Success Rates

Success rates vary depending on several factors:

Embryo factors:

• Quality and grading of the embryo

• Day 3 vs day 5 (blastocyst) stage

• Survival after thawing

• Genetic normalcy (PGT-tested embryos usually have higher chances)

Patient factors:

• Age at egg retrieval (not at transfer)

• Uterine health and receptivity

• Overall health and lifestyle (smoking, alcohol, stress, weight)

• Previous pregnancy history

Clinic factors:

• Laboratory expertise in freezing/thawing

• Precision of embryo transfer technique

• Individualised treatment approach

Comparison with fresh transfer:
Studies show that FET often offers equal or better results than fresh transfer. The uterus is more receptive when not under the influence of ovarian stimulation drugs, giving embryos a better chance to implant.

Step-by-Step Frozen Embryo Transfer Timeline

1. Pre-Transfer Stage (4–6 weeks before)

• Consultation and cycle planning

• Blood tests, ultrasounds, and medical clearance

• Discussion on how many embryos to transfer

• Mock transfer (optional)

2. Medication & Monitoring Phase

Natural Cycle:

• Track ovulation through ultrasounds and blood work

• Progesterone started after ovulation

Medicated Cycle:

• Estrogen supplements for 2–3 weeks to prepare the uterine lining

• Progesterone added before transfer

• Monitoring with ultrasounds to confirm lining thickness (ideally 8mm or more)

3. Transfer Day

• Embryo thawed 2–4 hours before procedure

• Catheter used to gently place the embryo in the uterus under ultrasound guidance

• Procedure is painless and takes about 10–15 minutes

• Light rest for 15 minutes afterwards

4. The Two-Week Wait

• Continue medications as prescribed

• Implantation typically occurs between days 6–10 after transfer

• Beta HCG blood test scheduled around day 12–14 to confirm pregnancy

Preparing for Your FET

Physical Preparation

• Eat a nutrient-rich diet (lean proteins, whole grains, fruits, vegetables, healthy fats)

• Stay hydrated and limit caffeine

• Avoid alcohol, smoking, and recreational drugs

• Maintain moderate exercise (walking, yoga)

• Get 7–9 hours of sleep daily

Emotional Preparation

• Acknowledge that outcomes are uncertain

• Practice stress management (meditation, journaling, breathing exercises)

• Join fertility support groups or seek counselling

• Stay connected with your partner for emotional support

The Two-Week Wait: Coping Strategies

This waiting period can be stressful. Common symptoms like spotting, bloating, or mild cramps can be caused by both medications and early pregnancy.

Tips to cope:

• Avoid overanalysing every symptom

• Stay busy with work, hobbies, or light activities

• Limit internet searches about symptoms

• Wait for your scheduled beta HCG test before testing at home

Read more: Causes of Female Infertility: Symptoms, Risks & Treatments

Signs of a Successful FET

Some women may notice:

• Implantation spotting around day 6–8

• Breast tenderness, fatigue, or mild nausea

• Frequent urination or heightened sense of smell

Reminder: Only a blood test can confirm pregnancy. Lack of symptoms doesn’t mean failure.

If FET Doesn’t Work

Failed cycles are emotionally difficult, but they don’t mean the journey is over.

Possible reasons for failure:

• Embryo genetic abnormalities

• Uterine receptivity issues

• Unknown implantation factors

Next steps may include:

• Reviewing the cycle with your doctor

• Considering additional tests (ERA, hysteroscopy, genetic testing)

• Adjusting medication protocol

• Trying again in the next cycle

Frequently Asked Questions (FAQs)

1. How many embryos should be transferred?
Most clinics recommend single embryo transfer (SET) to reduce the risk of multiple births.

2. Can I exercise during FET?
Yes, light activities like walking and yoga are safe. Avoid heavy lifting and high-intensity workouts.

3. How much does FET cost?
Costs range from ₹2.5 lakh to ₹4.1 lakh per cycle (excluding medications). Insurance may cover part of it.

4. Do embryos survive the thaw?
With vitrification, survival rates are above 95%.

5. Can women with PCOS or endometriosis have FET?
Yes, FET is often recommended and has good outcomes with proper preparation.

Conclusion

Frozen Embryo Transfer has transformed the landscape of fertility treatment. It offers couples multiple chances at pregnancy from one IVF cycle, flexible timing, and often better outcomes compared to fresh transfers.

While the journey can feel overwhelming, knowing what to expect at each step makes it easier to navigate. From preparing physically and emotionally, understanding the timeline, and trusting your fertility team, you can approach FET with confidence.

Even if a cycle doesn’t succeed, advances in reproductive medicine and ongoing support from your care team mean there is always hope. Many couples go on to achieve successful pregnancies after one or more transfers.