Intracytoplasmic Sperm Injection (ICSI)
Intracytoplasmic Sperm Injection (ICSI) is one of the assisted reproductive techniques related to sperm. It is used to enhance the fertilization stage in in vitro fertilization (IVF) by injecting a single sperm directly into a mature egg. The fertilized egg is then placed into the woman’s uterus or fallopian tube.
ICSI is considered highly successful, with fertilization occurring in about 90% of cases. As with IVF, several factors can influence the success of pregnancy resulting from ICSI.
Indications for ICSI
ICSI can be used when there is a factor that prevents or makes fertilization difficult. It is most commonly used in cases of male infertility. These include:
Male Infertility Factors
- Low sperm count
- Poor sperm motility
- Poor sperm quality
- Inability of sperm to penetrate the egg
Azoospermia (Absence of Sperm)
This refers to little or no sperm in the semen and is divided into:
- Obstructive azoospermia: caused by blockage such as vasectomy, congenital absence of the vas deferens, or scarring due to previous infections
- Non-obstructive azoospermia: when the testes do not produce sperm properly
Repeated IVF Failure
ICSI may be used even when infertility is not related to sperm issues, such as in cases of repeated IVF failure.
Genetic Testing
ICSI can be used for couples planning genetic testing of embryos to detect inherited disorders.
ICSI Procedure Steps
1. Sperm Collection
Sperm is collected either through ejaculation or surgically extracted from the testicles using a small incision. Surgery is used when there is a blockage or a problem with sperm development. If sperm count is very low or absent, genetic testing may be recommended before starting the procedure.
2. Ovulation and Egg Retrieval
The woman is prepared for egg collection by receiving medications for about two weeks, such as:
- Gonadotropins
- Follicle-stimulating hormone (FSH)
These stimulate the ovaries to produce multiple eggs.
After the first week:
- Estrogen levels are checked
- Ultrasound is used to monitor egg development
During the second week:
- Medication doses may be adjusted
Once follicles are fully developed:
- Human chorionic gonadotropin (hCG) is given to trigger maturation
- Eggs are retrieved 34–36 hours later using laparoscopy or ultrasound-guided needle aspiration
3. Fertilization and Embryo Transfer
The egg is placed in a special dish, and a single sperm is injected into it. After fertilization:
- The fertilized eggs are examined
- One or more embryos are selected
- The embryo(s) are transferred into the uterus using a thin flexible tube inserted through the cervix
Remaining embryos may be frozen for future use.
Disadvantages and Risks of ICSI
ICSI carries slightly higher risks compared to some other fertility treatments, including:
Miscarriage Risk
There may be an increased risk of miscarriage due to the use of sperm that may have difficulty fertilizing the egg naturally.
Egg Damage
Eggs may be damaged during the procedure.
Embryo Disorders
ICSI may be associated with certain risks to embryos, although evidence is not conclusive. These include:
- Rare genetic or physical abnormalities (e.g., hypospadias)
- These issues may be related to underlying infertility rather than the procedure itself
Future Infertility Risk
There is a possibility that male infertility may be inherited by male offspring, though this is not yet fully confirmed due to the relatively recent use of ICSI.
Ovarian Hyperstimulation Syndrome (OHSS)
Hormonal medications used to stimulate ovulation may cause this condition. However, the risk can be reduced by careful monitoring of hormone levels and ovarian response.
Multiple Pregnancy
The likelihood depends on the number of embryos transferred.
High Cost
ICSI is more expensive than standard IVF procedures.