What is intracytoplasmic sperm injection (ICSI)?
Intracytoplasmic sperm injection (ICSI) is an in vitro fertilisation procedure in which a single sperm is injected directly into an egg; this procedure is most commonly used to overcome male infertility problems. With conventional IVF, one can expect approximately 75% of the oocytes (eggs) to fertilize if they are healthy and the sperm parameters are not severely abnormal.
However, when there are severe sperm defects in count, motility or morphology, prolonged unexplained infertility, or abnormalities of the oocyte membrane or protein coat, there may be severely reduced fertilization or none at all.
Fertilization involves a complex series of physical and biochemical events, which take place between the egg and sperm. Conventional IVF overcomes the need for the sperm to swim long distances to reach the egg. However, the sperm must still be able to secrete enzymes to enable it to move through the cumulus mass, which surrounds the egg, be able to attach to and drill through the protein coat (zona pellucida) which protects the egg, and to attach to the egg membrane. The egg must be able to engulf the sperm and to cause the sperm head to swell and become a male pronucleus. This will then combine with the female pronucleus to complete the process of fertilization. Failure of any of these steps will result in no fertilization.
Intracytoplasmic Sperm Injection (ICSI) is used to treat severe male infertility. Male infertility is a lowering of a male's sperm count or sperm quality sufficient to reduce a patient's chance of pregnancy. Male infertility is often classified as mild, moderate or severe based on the number of motile sperm and the number of normally-shaped sperm in a man's semen. Men with fewer than five million sperm or fewer than 10 percent normally-shaped sperm are classified as having severe male infertility.
During IVF, patients who do not have male infertility have their eggs inseminated by a standard insemination procedure that involves placing a small volume of specially prepared motile sperm with the eggs in a dish. The process of fertilization is complex and requires sperm to function normally. The sperm from men with male infertility often do not possess normal sperm functions. Therefore, when sperm and eggs are simply placed together in a dish, as is done in the standard insemination procedure, the eggs often do not fertilize.
The ICSI technique was developed to assist the fertilization process in patients with severe male infertility. ICSI is a highly successful procedure that involves injecting one sperm directly into the egg using a microscope equipped with specialized micromanipulation equipment. The first step in ICSI involves selecting a normal-appearing sperm for injection into the egg. The sperm is then inserted into the egg using a micropipet.
The ICSI procedure can be used successfully to treat a wide array of male infertility disorders, such as low sperm counts, low sperm motility, or abnormally-shaped sperm. ICSI may also be used to treat a condition called azoospermia, which is the complete absence of sperm in the man's ejaculate. When no sperm are present in the ejaculate, the sperm aspiration techniques, Epididymal sperm aspiration and Testicular Sperm Extraction (TESE) may be used to obtain sperm from the male's reproductive tract. These sperm may then be used in conjunction with IVF and ICSI.
More information on infertility
What is infertility? - Infertility is the inability to achieve and/or maintain pregnancy. Infertility may due to a variety of causes, including abnormal hormonal levels, low sperm production and scarring of the fallopian tubes.
What causes infertility in men? - The most common male infertility factors include azoospermia and oligospermia. In rare cases, infertility in men is caused by a genetic disease such as cystic fibrosis or a chromosomal abnormality.
What causes infertility in women? - The most common female infertility factor is an ovulation disorder. Other causes of female infertility include blocked fallopian tubes. Inability of the fertilized egg to implant in the uterus will lead to female infertility.
What causes infertility? - Causes of infertility include a wide range of physical as well as emotional factors. Infertility can be caused by any interruption in the usual process of fertilization, pregnancy, and birth.
How is infertility diagnosed? - In the male, sperm examination and sperm count is commonly done. In females, the basal body temperature is recorded each morning over several months to find any ovulatory disorders.
What female fertility tests are available? - Blood tests that measure the levels of various hormones. The doctor may want to measure the man's testosterone levels to see if they are high enough. Basal body temperature (BBT) can be measured at home using a special thermometer to help predict the most fertile days.
What male tertility tests are available? - A semen analysis is the most common testing procedure for determining if there is a male infertility factor. Semen analysis is the mainstay of male testing.
What treatments are available to cure infertility? - The ultimate goal of infertility treatment is a healthy pregnancy and the birth of one healthy infant. There are various treatments for infertility, depending what the problem is.
What is assisted reproductive technology (ART)? - Assisted reproductive technologies are medical treatments to overcome infertility. The most common type of ART is in vitro fertilization.
What are the treatments for female infertility? - Assisted reproductive technology (ART) combines the use of fertility drugs - hormonal therapy with artificial insemination using any of a group of techniques. Acupuncture may also be helpful.
What medicines treat female infertility? - Clomiphene triggers the release of FSH and LH, boosting egg growth and helping the ovaries release a monthly egg. Bromocriptine suppresses a hormone called prolactin. LH-RH drugs are used when the pituitary or hypothalamus gland is not producing hormones.
What are the treatments for male infertility? - Low sperm counts can be treated by collecting and concentrating healthy sperm for insemination or assisted reproductive technology (ART) treatment.
How to prevent infertility? - Most types of infertility cannot be prevented. Smoking has been linked to low sperm counts. Alcohol affects the fertility of both men and women. Excessive exercise can lead to menstrual disorders in women and affect sperm production in men.
What is in vitro fertilization (IVF)? - In vitro fertilization (IVF) is the process used to conceive a child outside the body. In vitro fertilization is a method of assisted reproduction that involves removing eggs from a woman's ovary, combining the egg with sperm in a dish and replacing the resulting embryos in the woman's uterus.
What is intrauterine insemination (IUI)? - Intrauterine insemination is a procedure in which a fine catheter is inserted through the cervix into the uterus to deposit a sperm sample directly into the uterus.
What is gamete intrafallopian transfer (GIFT)? - Gamete intrafallopian transfer (GIFT) is an infertility treatment in which eggs are removed from a woman's ovaries, and placed in one of the fallopian tubes, along with the man's sperm.
What is intracytoplasmic sperm injection (ICSI)? - Intracytoplasmic sperm injection (ICSI) is an in vitro fertilisation procedure in which a single sperm is injected directly into an egg.
What is zygote intrafallopian transfer (ZIFT)? - Zygote intrafallopian transfer (ZIFT) is technique in which a woman's egg is fertilized outside the body, then implanted in one of her fallopian tubes.