Frozen Sperm vs Fresh: What the Evidence Says About Success Rates

Frozen sperm performs about as well as fresh sperm in IVF. Freezing and thawing does reduce motility, but it does not translate into worse outcomes: a 2024 study in Frontiers in Endocrinology found fertilization rates of 68.3 percent with frozen sperm against 67.5 percent with fresh, with clinical pregnancy and live birth rates statistically similar. An analysis of 7,969 cycles published in Human Reproduction of oocyte donation cycles using sperm from men with normal semen parameters found no significant difference in live birth rate. For most couples the choice is therefore about logistics rather than about outcomes.

How does sperm freezing work?

Sperm is first prepared in the laboratory to separate the most motile cells, then mixed with a cryoprotectant solution that shields the cells during freezing. The sample is cooled rapidly so that ice crystals, which would damage the cells, do not form. It is then stored in liquid nitrogen and thawed under controlled conditions when needed.

Why sperm is frozen

• Fertility preservation before chemotherapy, radiotherapy or surgery that may affect fertility.
• Donor sperm, which is frozen and quarantined as a matter of course.
• Cycle timing, where a partner cannot be present on the day of egg retrieval.
• A backup sample, so a cycle is not lost if a fresh sample cannot be produced on the day.

Does frozen sperm affect fertilization and embryo quality?

The 2024 study in Frontiers in Endocrinology reported motility falling from around 82 percent to 75 percent after freezing and thawing, yet fertilization rates were nearly identical at 68.3 percent with frozen sperm and 67.5 percent with fresh. Clinical pregnancy rates were 44.7 percent with frozen against 51.8 percent with fresh, and live birth rates 40.3 percent against 42.4 percent, differences the authors reported as not statistically significant.

Where sperm is retrieved surgically rather than ejaculated, the picture is similar. A 2025 study in the Asian Journal of Andrology comparing fresh and frozen micro-TESE sperm reported fertilization rates of 44.8 percent with fresh and 46.8 percent with frozen, with embryo quality and pregnancy outcomes aligned. Surgical retrieval is covered on our TESA, PESA and TESE page.

What about DNA damage and ICSI?

The analysis of 7,969 cycles published in Human Reproduction looked at cycles using sperm from men with normal semen parameters and found no significant difference in pregnancy or live birth rates between fresh and frozen sperm. Note that these were oocyte donation cycles, a design that holds egg quality relatively constant and so isolates the effect of the sperm. Because ICSI involves selecting and injecting a single sperm, a drop in overall motility matters less than it would in conventional insemination.

What are the practical trade-offs?

Situation	Fresh	Frozen
Partner can attend on the day of egg retrieval	Suitable	Suitable
Partner is traveling or cannot attend	Not possible	Suitable
Timing may be disrupted by illness or surgery	Risky	Suitable
Donor sperm is being used	Not applicable	Standard
Fertility preservation before cancer treatment	Not applicable	Standard

The main trade-off with freezing is the loss of motility on thawing. Laboratories account for this by preparing and selecting from the sample after thawing, and by using ICSI where appropriate. The main trade-off with relying on a fresh sample is that it has to be produced on a fixed day, which is why many couples bank a backup sample even when they intend to use fresh.

What should you ask your fertility team?

• If donor sperm is being used, how the laboratory assesses the sample after thawing, and whether ICSI is used routinely.
• Whether banking a backup sample ahead of retrieval day is advisable in your case.
• How your own results, rather than published averages, bear on the choice.

We at Millennium IVF Clinic work with both fresh and frozen samples. You can arrange a consultation with our team to discuss which suits your treatment plan.

Frequently asked questions

Is frozen sperm less likely to result in a pregnancy?

The studies above found pregnancy and live birth rates statistically similar between fresh and frozen. Motility drops on thawing, but that has not translated into a meaningful difference in outcomes in these datasets.

How long can sperm be frozen for?

Storage in Thailand is governed by the Protection of a Child Born by Medically Assisted Reproductive Technology Act B.E. 2558 (2015), which delegates the storage period to the Medical Council of Thailand rather than fixing one in the Act. Ask us what period applies and what you need to sign. Note that section 41 prohibits importing or exporting sperm, eggs or embryos, so material stored here cannot be moved abroad.

Does freezing damage sperm DNA?

The cohort study above found no significant difference in pregnancy or live birth outcomes between fresh and frozen sperm from men with normal semen parameters. Discuss DNA fragmentation testing with your specialist if it has been raised in your case.

Should I bank a backup sample?

Many couples do, so that a cycle is not lost if a fresh sample cannot be produced on the day of retrieval. Whether it is worth it in your case is a question for your specialist.