Frozen vs Fresh Embryo Transfer: Which Is Better for You?

Should you transfer an embryo immediately after egg retrieval, or freeze everything and come back later? This question has become increasingly relevant as "freeze-all" protocols have gained popularity — and as more patients travel abroad for treatment.

The answer isn't straightforward. Fresh and frozen embryo transfers each have advantages, and the best choice depends on your specific circumstances. This guide breaks down the evidence, compares success rates, and helps you understand when each approach makes sense.

Understanding the Two Approaches

Success Rate Comparison

The question everyone asks: which approach has better success rates? The answer has evolved as freezing technology has improved.

Overall Success Rates

For unselected patients (everyone, regardless of risk factors), success rates are now similar between fresh and frozen transfers. A 2021 Cochrane Review analyzing 15 randomized controlled trials with over 4,700 women found no significant difference in cumulative live birth rates between the two strategies.

Without PGT-A testing, typical live birth rates are approximately 44% for fresh transfers and 46% for frozen transfers — statistically equivalent.

The Age Factor

Here's where it gets interesting. While overall rates are similar, the advantage shifts toward frozen transfers as women get older:

Why do older women see such a dramatic FET advantage? The likely reason is that stimulation takes a greater toll on older women's bodies, making the uterine environment less hospitable immediately after retrieval. Waiting allows recovery.

When Freeze-All Is Strongly Recommended

Certain situations make freeze-all the clear choice:

OHSS Risk

If you're at high risk for ovarian hyperstimulation syndrome — high AMH (>10 ng/mL), PCOS, more than 15-20 follicles, or very high estradiol levels — freeze-all significantly reduces your risk. Fresh transfer when the ovaries are hyperstimulated can worsen OHSS; pregnancy hormones make it last longer and become more severe.

The 2021 Cochrane Review found OHSS rates of 1% with freeze-all versus 3% with fresh transfer.

Elevated Progesterone at Trigger

If your progesterone rises above 1.5 ng/mL before your trigger shot, the uterine lining may have already shifted out of sync with embryo development. This "premature luteinization" reduces implantation rates with fresh transfer but doesn't affect future FET cycles.

PGT-A Testing

If you're doing preimplantation genetic testing, the results take 7-14 days to return — long after a fresh transfer would need to occur. Freeze-all is necessary to wait for results and transfer only chromosomally normal embryos.

Uterine Issues Requiring Treatment

If hysteroscopy reveals polyps, fibroids, or adhesions, these should be treated before transfer. Freeze-all allows time for surgical correction and uterine healing.

"Egg Banking" Cycles

Some women, particularly those with low ovarian reserve, do multiple retrieval cycles to accumulate embryos before testing and transferring. Freeze-all is inherent to this approach.

When Fresh Transfer May Be Preferred

Fresh transfer still has a place, particularly when:

• Good response without OHSS risk: Normal egg count, no elevated progesterone, healthy estradiol levels
• Cost constraints: Freezing, storage, and FET add $2,000-$4,000 to treatment costs
• Time sensitivity: Age is advancing rapidly and waiting another cycle matters
• Travel limitations: Making two trips abroad is difficult or expensive
• Personal preference: Some women prefer to transfer immediately rather than wait

FET Protocols Explained

If you choose or need a frozen embryo transfer, there are several protocol options:

Medicated (Programmed) FET

This is the most common FET protocol. You take estrogen (pills, patches, or injections) to build your uterine lining to at least 7mm. Once the lining is ready, you add progesterone for 5 days, then transfer occurs.

The downside: you'll need daily medications for 10-12 weeks if the transfer is successful, until the placenta takes over hormone production.

Natural Cycle FET

In a natural cycle FET, you don't take estrogen — your body grows the lining naturally. The clinic monitors your cycle with blood tests and ultrasounds, identifies when you ovulate, and times the transfer accordingly.

Emerging evidence suggests natural cycle FET may have lower rates of hypertensive disorders and pre-eclampsia during pregnancy. However, it requires regular cycles and has 5-20% cancellation rates if ovulation doesn't occur as expected.

Modified Natural Cycle

This hybrid approach lets your body grow the lining naturally but uses a trigger shot to control ovulation timing, making scheduling more predictable while avoiding extended estrogen use.

What Happens to Frozen Embryos?

Modern vitrification (flash-freezing) has revolutionized embryo preservation. Survival rates after thawing are now 95-99% at quality labs — embryos frozen for years perform just as well as those frozen for weeks.

Storage Considerations

Travel Implications: FET for Fertility Tourism

If you're traveling abroad for IVF, the fresh vs. frozen decision has significant practical implications.

For many international patients, freeze-all makes logistics easier. You can complete egg retrieval during one trip, then schedule your FET trip with certainty — knowing exactly when you need to arrive and when you can leave.

Embryo Shipping

If you freeze embryos abroad, you have the option to ship them to your home country for transfer at a local clinic. International embryo shipping typically costs $400-$1,000 and requires coordination between clinics.

Alternatively, you can leave embryos stored at your Colombian clinic and return for each FET attempt — often more cost-effective given Colombia's lower storage and FET cycle costs.

Cost Comparison

Freeze-all costs more upfront but can save money if you have multiple embryos — subsequent FET cycles cost far less than new IVF cycles. If your first transfer doesn't work, you have frozen embryos ready for another attempt without repeating the expensive stimulation and retrieval process.

Pregnancy Outcomes: Any Differences?

Beyond pregnancy rates, researchers have looked at whether the transfer type affects pregnancy outcomes.

FET May Have Advantages

• Lower pre-eclampsia: Some studies show reduced hypertensive disorders with natural cycle FET (though not necessarily with medicated FET)
• Lower preterm birth: Marginally lower rates with FET in some analyses
• Better placentation: The "more natural" uterine environment may support better placental development

FET May Have Disadvantages

• Slightly higher birth weight: FET babies tend to be slightly larger, which is a minor concern
• Possible LGA risk: Some data suggests higher rates of large-for-gestational-age babies with FET

Overall, both approaches produce healthy pregnancies and babies. The differences in outcomes are modest and shouldn't drive your decision.

Making Your Decision

Here's a framework to help you decide:

Strong Case for Freeze-All

• You're at risk for OHSS (high response, PCOS, AMH >10)
• Progesterone elevated at trigger (>1.5 ng/mL)
• You're doing PGT-A testing
• You're 38 or older
• You have uterine issues needing treatment
• You want scheduling flexibility for travel

Reasonable Case for Fresh Transfer

• You're under 37 with good response
• No OHSS risk factors
• Normal progesterone at trigger
• Not doing PGT-A
• Cost is a significant constraint
• You prefer a single trip and immediate transfer

When It Truly Doesn't Matter Much

• You're under 35
• Normal response without risk factors
• Either option fits your situation
• Your clinic recommends either approach

Questions to Ask Your Clinic

1. "What are your success rates with fresh vs. frozen transfers for my age group?"
2. "Given my response/situation, which do you recommend and why?"
3. "What is your embryo thaw survival rate?" (Should be >95%)
4. "If I freeze all, what FET protocols do you offer?"
5. "What are the costs for freezing, storage, and FET?"
6. "Can I ship embryos to my home country if needed?"

The Bottom Line

Fresh and frozen embryo transfers are both excellent options with similar overall success rates. The "best" choice depends on your individual circumstances:

If you're younger than 37 with no risk factors, either approach works well. Choose based on your preferences, logistics, and cost considerations.

If you're 38 or older, have OHSS risk factors, or need PGT-A testing, freeze-all followed by FET likely gives you the best chances.

If you're traveling internationally for treatment, freeze-all often makes logistics easier and gives you more scheduling control.

Discuss your specific situation with your fertility specialist. The right answer is the one tailored to your circumstances, not a one-size-fits-all approach.

Read more: Embryo Grading Guide | Two-Week Wait Survival | IVF Trip Timeline