CI vs. ICSI: understanding the differences and choosing the best IVF fertilization method
If you are one of the over one million people in the US who turn to IVF to build their family, you’ve likely heard about Conventional Insemination (CI) and Intracytoplasmic Sperm Injection (ICSI).
In this blog, we’ll explain the IVF process with and without ICSI to help you navigate your options with confidence. Here at our East Bay fertility clinic, we are passionate about helping people grow their families and are committed to providing the guidance you need to make informed decisions on your fertility journey.
How does fertilization happen in IVF?
In Vitro Fertilization (IVF) is one of the most well-known fertility treatments. It involves retrieving eggs from the ovaries and fertilizing them with sperm in our state-of-the-art lab, where our expert embryologists use one of two methods:
Conventional Insemination (CI)
In conventional IVF, a single egg is placed in a culture dish and surrounded by about 50,000 motile (swimming) sperm. The sperm naturally competes to fertilize the egg, mimicking the way fertilization happens inside the body.
Intracytoplasmic Sperm Injection (ICSI)
With ICSI, our embryologists carefully select one healthy sperm and inject it directly into a mature egg using a specialized microscope and microneedle. This method bypasses the natural sperm competition and is particularly beneficial when sperm quality is a concern.
Both approaches occur outside the body in a controlled laboratory setting, ensuring the highest precision and care.
How are CI and ICSI similar?
Both CI and ICSI share the same fundamental steps:
- Ovarian stimulation – Hormonal medications help stimulate the ovaries to produce multiple eggs.
- Egg retrieval – Using a minimally invasive procedure, mature eggs are collected from the ovaries.
- Fertilization: Sperm are introduced to the eggs in our lab through conventional insemination (CI) or Intracytoplasmic Sperm Injection (ICSI).
- Embryo development – Fertilized eggs (embryos) grow in a controlled environment. We use independent chamber incubators, allowing embryos to remain undisturbed as they develop into the blastocyst stage.
- Genetic Testing – Patients can test embryos before transfer to improve success rates, including screening for chromosomal normality and diagnosing inherited conditions when one or both parents are carriers.
- Embryo transfer – A healthy embryo is transferred into the uterus in hopes of implantation and pregnancy.
- Pregnancy test – About two weeks after the transfer, patients return to the clinic for an ultrasound to determine whether the embryo implanted successfully.
How are CI and ICSI different?
The primary difference between CI and ICSI lies in how fertilization occurs. In CI, sperm is placed in a lab dish with the egg, allowing fertilization to happen naturally. In ICSI, an embryologist selects a single healthy sperm and injects it directly into the egg, ensuring fertilization even when sperm quality or quantity is a concern. Because ICSI bypasses the natural sperm selection process, it is often recommended for male factor infertility or for individuals who have experienced failed fertilization in previous IVF cycles.
Who might benefit from ICSI?
Our care team will meet with you and carefully assess your history, health, and family-building goals to determine which fertilization method will provide the best chance of success. We commonly recommend ICSI for:
- Male factor infertility, including low sperm count, poor motility, or poor morphology.
- Previous IVF cycles with failed fertilization
- Surgically retrieved sperm, such as in cases of azoospermia
- Genetic testing of embryos when preimplantation genetic testing is being utilized (PGT)
- Using frozen eggs
- When there are very few eggs available
- Low egg yield
- Poor or failed fertilization in a past cycle
What are the risks of CI vs ICSI?
When comparing conventional insemination (CI) and intracytoplasmic sperm injection (ICSI), one important factor to consider is the risk of total fertilization failure (TFF). With CI, the risk of TFF during an IVF cycle is estimated at 10–15%, while ICSI significantly lowers that risk to around 2–3% (Mahutte & Arici, 2003). This difference is one reason why ICSI is often recommended in certain cases, especially when there are concerns about sperm quality or previous fertilization issues.
How much does IVF cost?
We create a safe and supportive environment characterized by transparency, collaboration, and clear communication in every aspect of our Bay Area IVF clinic, from fertility testing and treatments to financial services. Our dedicated financial counselors help our patients get the most out of available fertility treatment insurance benefits. We will work diligently to connect you with financing programs so you can focus on growing your family.
How do I choose the right fertility treatment?
We recognize that every fertility journey–like every family–is unique. Collab’s patient-first approach ensures that your voice is heard, and our state-of-the-art lab provides the highest precision and care. Whether conventional CI or ICSI is right for you, we are here to guide you every step of the way.
Have questions? Schedule a consultation with our fertility experts today. We’re honored to be part of your journey.
________________________
Proudly Supporting Local Communities
Collab Fertility is honored to serve families in the East Bay like Danville, Alamo, Orinda, Lafayette, Moraga, Piedmont, and Walnut Creek, as well as many other communities in the Bay Area and beyond, including Oakland, San Ramon, Concord, Pleasant Hill, Santa Rosa, Novato, Napa, Sonoma, and more.
Latest Articles
Navigating IVF with confidence: how Collab supports you financially
