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What is ICSI? How Is It Different from IVF?

Intracytoplasmic Sperm Injection, more commonly referred as ICSI, is potent fertilization method used in the In Vitro Fertilization (IVF) process. The only difference between standard IVF and ICSI is in the method used to allow the sperm to fertilize the egg. This adjunct procedure has helped millions of couples overcome their infertility issues.

But what exactly is ICSI and who needs it? In this article, you will find all the answers.

What is ICSI? How Is It Different from IVF?

In Vitro Fertilization (IVF) is a technique used to help couples who are unable to conceive through natural reproduction. IVF allows them to be able to have a baby safely through fertilization in the laboratory and transferring a good embryo back to the woman’s uterus.

The ICSI process follows every step of conventional IVF except the fertilization step where, instead of letting the eggs and sperm fertilize on their own in a laboratory dish, using ICSI a single healthy sperm is selected and directly injected into a mature egg to achieve fertilization.

ICSI is usually used when a couple faces male-factor infertility that is too severe to be treated by traditional IVF. ICSI is a technically more advanced form of IVF.

When is ICSI usually used?

ICSI is usually used when patients suffer from one or more following issues:

  • High numbers of abnormally shaped sperm
  • Poor sperm movement
  • Low sperm counts
  • An obstruction in the male reproductive system preventing sperm ejaculation
  • Poor or no fertilization using conventional IVF, regardless of the condition of the sperm
  • Where frozen eggs are used.
  • Where the sperm has high DNA fragmentation
  • Couple have genetic risks and will use PGT (preimplantation genetic testing)

In all of the above, conditions ‘using PGT’, using conventional IVF will likely have poor outcomes and ICSI treatment is recommended. ICSI is used in PGT to avoid sources of DNA contamination.

How is ICSI done?

ICSI  comprises five steps as follows:

  1. Stimulate egg reproduction

Starting on the 2nd or 3rd day of a woman’s menstrual cycle, she will meet with her doctor to receive blood tests and an ultrasound. If the results of the tests are positive for potential success, the doctor will prescribe medicines to stimulate the woman’s ovarian follicles. Each follicle contains an egg, so it is basically stimulating egg production. This stimulation is an injection every day for 10-14 days. The woman will have a doctors consult every 3-4 days for further blood tests​ and transvaginal ultrasound to check her ovaries and follicle growth. Once the follicles are of a suitable size, the woman will receive a “trigger shot”, an injectable medication to complete the eggs maturity.  About 36 hours after the trigger shot, the doctor shall perform the egg retrieval.

2. Retrieve and select eggs and sperm

About 36 hours after the trigger shot, the doctor will sedate the woman to keep the process comfortable and painless, and, using ultrasound imaging, will guide a thin needle into the pelvic captivity and retrieve the eggs from the ovarian follicles.

Usually from 1-2 hours before to around the same time as the egg retrieval process, (unless frozen sperm is being used) the male partner will collect semen. The semen is washed and prepared for the ICSI process which is usually done about 2 hours after the egg retrieval process.

3. ICSI, inject a selected sperm into a selected egg

Under a microscope, an embryologist will select a normal shaped fast-moving sperm, using a thin micropipette, and will inject that single healthy sperm directly into a mature egg. This will be repeated individually for each mature egg. The next morning the eggs will be checked for “normal” fertilization. Once fertilization has occurred, the fertilized egg is considered an embryo.

4. Culture the embryo

The embryos will be cultured for 5-6 days in the laboratory until they develop or grow to the blastocyst stage. After embryos reach the blastocyst stage, only healthy and strong blastocysts will be selected for transfer into the woman’s uterus, or for freezing.

5. Transfer the embryo

Following the culture process, a selected blastocyst(s) can be transferred to the woman’s uterus in a simple and painless procedure where a catheter containing the blastocyst(s) is ultrasound guided through the vagina and cervix and the blastocyst(s) deposited in the uterus. The blastocyst(s) will implant into the uterine wall (endometrium) and begin to develop and grow. About 7-10 days after the embryo transfer, the woman should take a blood pregnancy test to find out if she is pregnant. An ultrasound can be performed about 2 weeks after to confirm the pregnancy.

How successful is ICSI?

Fertilization rates for conventional IVF and ICSI are about the same, with generally ~70 % of the eggs getting fertilized. After fertilization, the pregnancy success rate is also the same between standard IVF and ICSI, and is usually in the range of between 40-70% depending on various factors including age, reason for infertility diagnosis, fertility drugs used, and other underlying fertility concerns. Direct consultation with your ICSI doctor will be able to help you get a more precise and accurate assessment of your likely success rate.

What are the risks of ICSI?

ICSI is generally a safe procedure, but like every medical process, it is not without risk. The most common risks of ICSI include:

  • Egg damage: Because an egg is quite fragile, during the ICSI procedure the egg may be damaged as a result of the needle insertion. Choosing a good clinic with an excellent laboratory and expert embryologists will reduce the risk of damage to the eggs during the ICSI process.
  • Chromosomal abnormalities, autism, intellectual disabilities, and birth defects: Some studies have suggested that ICSI is associated with a slightly increased risk of some disorders as compared to standard IVF and natural pregnancy.
  • Multiple pregnancies: Multiple pregnancies may occur at the same rate as in natural pregnancy. However, if more than one embryo is transferred the risk of multiple pregnancies is increased.  The chance of a multiple pregnancy (twins/triplets, etc.)  can be reduced by only transferring a single embryo.
  • Ovarian Hyperstimulation Syndrome:  Potential side effects of using fertility drugs to stimulate ovarian follicle growth are bloating, tenderness, and nausea. If not monitored these can become serious. Fortunately, good clinics monitor and adjust your cycle, and OHSS is very rare.

Carefully selecting an ICSI clinic is therefore important. A promising ICSI clinic should be well-equipped with the latest range of medical equipment and technologies, have high-quality, well-maintained laboratories, a team of credentialed experts, and a good track record of ICSI success.

About Superior A.R.T.

Superior A.R.T offers comprehensive fertility and genetic services in state-of-the art Assisted Reproduction Technology (A.R.T.) Laboratories in Bangkok Thailand. Superior A.R.T. was founded in 2007 by a group of leading Thai Infertility specialists in collaboration with Australian world leading fertility and A.R.T. treatment providers, Superior A.R.T is a renowned fertility clinic offering comprehensive fertility and genetic services by a team of experienced treatment providers and researchers specifically specializing in Assisted Reproduction Technology – A.R.T. Superior A.R.T. is committed to making your dream of having a healthy baby come true. 



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