ICSI — Advanced Fertilization Technique
ICSI is a precision fertilization technique in which a single sperm is injected directly into an egg. It has transformed outcomes for male factor infertility and is now used in the majority of IVF cycles worldwide — including all PGT cycles at IRFC.
In a standard IVF cycle, eggs and a concentrated sperm sample are placed together in a culture dish and fertilization occurs naturally. In ICSI, an embryologist uses a specialized glass needle to select a single morphologically normal, motile sperm and inject it directly into the cytoplasm (interior) of a mature egg.
The injected egg is then cultured and monitored in the same way as conventionally fertilized eggs. By the next morning, fertilization is confirmed by the appearance of two pronuclei — one from the egg and one from the sperm.
ICSI was first performed successfully in 1992. Today it is performed in approximately 65–70% of all IVF cycles globally and has a well-established safety and efficacy record spanning over three decades.
ICSI is a highly technique-dependent procedure — outcomes vary significantly based on the skill and experience of the embryologist performing the injections. IRFC's embryology team has performed tens of thousands of ICSI procedures and our laboratory ranked #1 in the United States for IVF success rates in 2016.
Our embryology team includes laboratory director Dr. Yufen Xie, PhD, who oversees all ICSI and advanced fertilization procedures.
All embryos — ICSI or conventionally fertilized — are cultured in our EmbryoScope+ time-lapse incubators, capturing continuous development images without disturbing the culture.
IRFC uses the latest micromanipulation systems and Piezo-ICSI techniques for eggs that benefit from gentler injection methods.
ICSI is recommended in specific clinical situations where conventional fertilization is unlikely to succeed or is not appropriate.
Very low sperm count (oligospermia), poor motility (asthenospermia), or abnormal morphology (teratospermia) — even a single motile sperm is sufficient for ICSI.
When sperm are obtained via TESA, PESA, or micro-TESE due to azoospermia (absence of sperm in the ejaculate), ICSI is the only fertilization method available.
Patients who have previously completed an IVF cycle with low or failed fertilization using conventional insemination are typically moved to ICSI in subsequent cycles.
Sperm that has been cryopreserved (frozen) may have reduced motility after thawing. ICSI ensures each egg has the best chance of fertilization regardless of sperm mobility post-thaw.
When embryos will be biopsied for genetic testing, ICSI is preferred to eliminate the risk of stray sperm contaminating the biopsy sample and affecting results.
When only a small number of mature eggs are retrieved, ICSI maximizes the fertilization rate to make the most of every available egg.
Precision, down to a single cell.
ICSI replaces the conventional fertilization step within an IVF cycle — the stimulation, monitoring, egg retrieval, embryo culture, and transfer are identical. If you are considering IVF and have any of the indications above, your physician will recommend ICSI as part of your cycle plan. The full IVF process guide explains each phase in detail.
ICSI consistently improves fertilization rates compared to conventional insemination, particularly for male factor cases. However, fertilization rate is not the same as live birth rate — overall IVF success depends on embryo quality, uterine receptivity, and other factors. For patients with normal sperm parameters, ICSI and conventional insemination produce similar blastocyst and live birth rates. Your physician will recommend ICSI when the evidence supports it for your specific situation.
Decades of data on children born from ICSI show no clinically meaningful difference in health outcomes compared to children conceived naturally or via conventional IVF. ICSI is considered safe and is one of the most widely performed techniques in reproductive medicine worldwide.
ICSI is performed entirely in the laboratory on the retrieved eggs — there is nothing additional done to the patient. The egg retrieval process is identical whether or not ICSI is planned. You will not feel or experience anything different.
Not necessarily. For patients with normal semen parameters and no prior fertilization issues, conventional insemination (placing a concentrated sperm sample near the eggs in culture) is effective and avoids the additional laboratory step. ICSI is not universally recommended — it is used when evidence supports it.
Yes — in fact, PGT-A cycles at IRFC routinely use ICSI to prevent sperm DNA contamination during the embryo biopsy. The two techniques complement each other and are commonly performed together.
Your physician will determine whether ICSI is appropriate for your cycle based on semen parameters, prior treatment history, and planned add-ons. Schedule a consultation to discuss your full plan.