Intracytoplasmic Sperm Injection (ICSI)
ICSI at a glance
- ICSI can be used to inject a single sperm directly into a woman’s egg during the in vitro fertilization (IVF) procedure to aid in fertilization.
- ICSI is used for male infertility conditions or when previous IVF fertilization attempts have failed.
- ICSI fertilizes 50 percent to 80 percent of eggs.
Intracytoplasmic Sperm Injection (ICSI) is an assisted reproduction procedure to aid egg fertilization. During normal egg fertilization, a sperm attaches its head to the outside of the egg and pushes itself through the outer layer into the inside of the egg (cytoplasm). If a man has poor sperm quality or a low sperm count, ICSI can be used to inject a single sperm directly into the egg.
ICSI is used in conjunction with IVF. For traditional IVF, a man’s sperm are mixed with a woman’s egg in a small dish at a laboratory to achieve fertilization. ICSI, however, employs a tiny needle to inject the sperm into the egg’s center. Once this is complete, the IVF process continues as normal: the fertilized egg(s) grow in the lab for two to five days, then are transferred to the woman’s uterus to implant, grow and hopefully develop into a full-term pregnancy.
When ICSI is used
ICSI is used for male infertility conditions, such as:
- Low sperm production
- Irregular sperm shape or movement
- Sperm that have trouble attaching to the egg
- Blocked reproductive tract that keeps sperm from releasing
If traditional IVF fails to produce fertilization, ICSI can also be used even when sperm condition appears normal.
ICSI success rates
ICSI fertilizes 50 percent to 80 percent of eggs, according to the American Society for Reproductive Medicine. Lower results may occur if ICSI damages the egg, injected sperm does not result in fertilization, or the fertilized embryo stops growing.
Once fertilization does occur, the chance of giving birth to a single baby, twins, or triplets is the same as traditional IVF.
How ICSI affects a baby’s development
According to the American Society for Reproductive Medicine, a woman conceiving naturally has a 1.5 percent to 3 percent chance that the baby will have a major birth defect. However, birth defects after an ICSI procedure are rare, occurring in only a fraction of a percent of children conceived.
Conditions that have been associated with the use of ICSI include Beckwith-Wiedemann syndrome, Angelman syndrome, hypospadias, or sex chromosome abnormalities. Some infertility problems in ICSI-conceived children may be genetic – if the man whose sperm was used had infertility issues, boys conceived with the use of ICSI may also have infertility issues as adults.