ICSI (Intracytoplasmic Sperm Injection): When It Is Used

What is ICSI?

Intracytoplasmic sperm injection (ICSI) is a laboratory technique performed as part of IVF. Under a microscope, an embryologist picks up a single sperm with a very fine needle and injects it directly into the center of a mature egg. The egg is then watched for signs of fertilization, and resulting embryos are grown and transferred like those from conventional IVF.

How it differs from conventional IVF

When ICSI is recommended

• Severe male factor infertility, such as very low count, motility or abnormal shape
• Sperm retrieved surgically because none are found in the ejaculate
• Previous IVF cycles with failed or poor fertilization
• Frozen eggs, at many clinics
• Genetic testing (PGT) of embryos, to reduce contamination from extra sperm DNA

When it adds little

Large studies have not found a benefit for ICSI over conventional IVF when sperm parameters are normal. Because of that, professional societies recommend against its routine use for couples without a male factor. If your clinic suggests ICSI as an add-on, ask why it is recommended for you, what evidence supports it in your situation and how much it costs.

Safety

ICSI bypasses natural selection of sperm, so a small number of men with genetic causes of infertility may pass those on to sons. For that reason, severe male factor problems may warrant genetic counseling or testing first. Studies of children conceived by ICSI are generally reassuring, though some report slightly higher rates of certain birth defects after ART overall.

Questions to ask your clinic

• Is ICSI needed for us, or is it an optional add-on?
• What are the fertilization rates at this lab with and without ICSI?
• Should we have genetic counseling or testing first?
• What does it add to the cost?

Use our appointment questions planner to keep track.

What happens in the lab

On the day of retrieval, eggs are collected and the cumulus cells that surround them are removed so the embryologist can see each egg clearly. Only mature eggs can be injected. Using a microscope and a tiny glass needle, the embryologist immobilizes a sperm, draws it into the needle and injects it into the egg. The injected eggs return to an incubator, and the next day the embryologist checks for signs of fertilization. Not every egg fertilizes. A typical fertilization rate with ICSI is high, but it varies with egg and sperm quality.

Sperm selection

ICSI allows the embryologist to choose which sperm to inject. Selection is usually based on appearance and movement. Some labs use advanced techniques to select sperm, such as high-magnification sorting or tests of binding. Evidence that these methods improve live birth rates is limited, so ask what your lab does and whether it adds cost.

Surgical sperm retrieval and ICSI

When no sperm are found in the ejaculate, a urologist may retrieve sperm from the testicle (TESE or micro-TESE) or the epididymis (PESA). Even a few sperm can be enough for ICSI. Frozen sperm from retrieval is often used, which allows the egg retrieval to be scheduled separately. These procedures require coordination between the urologist and the fertility clinic. See fertility surgery.

Questions about outcomes

ICSI is a lab technique, so ask about the lab. Useful questions include the clinic’s typical fertilization rate with ICSI, the proportion of embryos reaching the blastocyst stage, and how its results compare with national data. Ask whether the clinic offers ICSI routinely or only when indicated.

Cost

ICSI typically adds a separate fee to an IVF cycle. If sperm are normal, ask whether ICSI is truly needed or can be left out. Where ICSI is medically indicated, it is generally considered essential rather than optional.

Emotional considerations

Some couples feel disappointed that fertilization will not happen naturally, or worried about what the technique means for their child. Evidence is generally reassuring, and many families find comfort in talking with their clinician and a counselor. See male factor infertility for the causes ICSI can address.

Next steps

If ICSI is suggested for you, ask about the reason, the alternatives and what testing should come first, such as genetic counseling. Use our appointment questions planner.

Frequently misunderstood points

People often assume ICSI is a “better” form of IVF, but it solves a specific problem: getting sperm into the egg. It does not improve egg quality, change embryo genetics or increase the chance that an embryo will implant. If fertilization is not the limiting step, ICSI will not help.

Another misunderstanding is that ICSI guarantees fertilization. It does not. Some eggs are not mature, some are damaged by the injection, and some fail to activate. A clinic should be able to tell you its typical rate and what happens if few eggs fertilize.

Planning ahead

If a male factor is already known, tell your clinic early so the lab is prepared, any surgical retrieval is arranged and genetic counseling happens before the cycle rather than during it. Careful planning reduces the stress of the retrieval day and avoids surprises.

Related reading

Male factor infertility · Male fertility testing · Fertility surgery including surgical sperm retrieval.