Intracytoplasmic Sperm Injection (ICSI)
Intracytoplasmic sperm injection (we just say ICSI “ick see” for short) is a procedure where a single sperm is manually inserted directly into an unfertilized egg. ICSI is performed by highly skilled embryologists using extremely sensitive tools called micromanipulators to inject sperm via tiny pipettes known as microinjectors. The procedure is performed with the assistance of an inverted microscope built into a specialized anti-vibration table. Embryologists perform sperm selection by observing the sperm at high magnification. Sperm that have a strong forward progression to their movement (motile), and a normal head shape and form (morphology) are the best candidates for ICSI.
When is ICSI Used?
Conceiving a child requires only a single healthy sperm to reach the egg. Infertility sometimes occurs when the sperm cannot penetrate the permeable barrier around the egg (the zona pellucida), cannot fertilize the egg, or cannot reach it. Often, issues with fertilization can arise as a result of male factor infertility. Research studies show that approximately one-third of all infertility cases are due to male infertility issues.
In IVF without ICSI, eggs, and sperm are placed in the culture media in an incubator so that fertilization can occur, but in some cases, fertilization does not occur. ICSI has been shown in multiple studies to increase the fertilization rate, and can therefore improve outcomes for these patients.
When a woman is believed to have a low ovarian reserve, or if few high-quality eggs are aspirated at retrieval, ICSI may be used simply to increase the likelihood of success.
ICSI Process Step By Step
ICSI is always performed in conjunction with IVF. Before we can perform ICSI, we need a healthy, mature egg(s). For most patients, this means several office visits over the course of a few months, numerous lab tests and ultrasounds, followed by an egg retrieval procedure during which our reproductive endocrinologist will aspirate as many mature eggs as possible. We also need sperm, which will be washed to separate individual sperm from the semen sample. Once both sperm and egg are on hand, ISCI can be performed at the micromanipulation workstation.
- One by one, each egg is positioned next to a specialized pipette with rounded edges that is designed to hold the egg during injection.
- Another specialized pipette with a sharp tip is used remove the tail and pick up a single sperm.
- With extreme care, the needle is inserted into past the zona (the hard outer shell of the egg) into the cytoplasm in the middle.
- The sperm is then injected into the middle of the egg and the pipette is pulled back.
- The egg and sperm are then placed into incubators and the next day our embryologist performs a fertilization check.
- As many as 85% of eggs that are injected via ICSI achieve fertilization. These fertilized eggs grow in the laboratory for five days while being carefully monitored for normal development milestones.
Pregnancy Success with ICSI
ICSI has had incredible success in treating male factor infertility, greatly increasing the chances of fertilization. This is often due to the high quantity of good quality, mature eggs retrieved from a female partner with normal fertility. In cases of extreme male infertility, it is often still possible for experienced embryologists to identify sperm with normal motility and morphology to use in ICSI. Even where no male factor issues are present, ICSI can greatly enhance the odds of successful pregnancy through IVF. This is thought to be due to increased fertilization rates versus standard IVF.