Intracytoplasmic sperm injection - ICSI

Overview

Intracytoplasmic sperm injection, or ICSI, is most commonly used to overcome male infertility problems, although it may also be used where eggs cannot easily be penetrated by sperm, and occasionally as a method of in vitro fertilization, especially that associated with sperm donation.

It can be used in teratozoospermia. Once the egg is fertilized, abnormal sperm morphology does not appear to influence blastocyst development or blastocyst morphology.Even with severe teratozoospermia, microscopy can still detect the few sperm cells that have a "normal" morphology, allowing for optimal success rate.

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How ICSI Works

The technique involves very precise maneuvers to pick up a single live sperm and inject it directly into the center of a human egg. The procedure requires that the female partner undergo ovarian stimulation with fertility medications so that several mature eggs develop (IVF). These eggs are then aspirated through the vagina, using vaginal ultrasound, and incubated under precise conditions in the embryology laboratory. The semen sample is prepared by centrifuging (spinning the sperm cells through a special medium). This solution separates live sperm from debris and most of the dead sperm. The micromanipulation specialist picks up the single live sperm in a glass needle and injects it directly into the egg.

Through the ICSI procedure, many couples with difficult male factor infertility problems have achieved pregnancy at UCSF. Fertilization rates of 70-80% (of all eggs injected) are currently being achieved, and pregnancy rates are comparable to those seen with IVF in couples with no male factor infertility.

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ICSI Frequently Asked Questions

• What is ICSI ?

ICSI is short for IntraCytoplasmic Sperm Injection. It is the term we use for the direct microinjection of a single sperm into a single egg in order to achieve fertilization. It was originally developed to assist fertilization in couples with severe male factor infertility in 1992.

• Is it for everyone ?

Generally speaking, the only situation where ICSI is considered absolutely necessary is in the case of male factor infertility with an abnormal semen analysis. However, in the Bay Area, approximately 75% of all IVF cases are now ICSI. Patients are electing to undergo ICSI for reasons other than male factor infertility. Those reasons include previous poor fertilization with IVF, decreased number of eggs for fertilization, variable sperm counts, and unexplained infertility. Thus, many patients choose to undergo the ICSI procedure in order to maximize their success even when the procedure may not be clearly indicated.

What is the experience of the UCSF IVF laboratory with the ICSI procedure?
The UCSF IVF laboratory was responsible for the first baby born from an ICSI procedure in the Bay Area in 1995. Our two ICSI embryologists have collectively over 12 years of ICSI experience. The most important indicator of ICSI success appears to be the fertilization rate achieved with the ICSI procedure. The fertilization rate using our ICSI technique in the UCSF IVF laboratory is exceptional (currently 80-85%). That is to say, on average for every ten eggs injected, 8 eggs will fertilize normally. As you can imagine, the procedure is a technically difficult one and requires meticulous control and precision to successfully perform (see picture).

• What are the risks of ICSI ?

There are several risks:

1. During the ICSI procedure, a small number of eggs (usually <5%) can be irreparably damaged as a result of the ICSI needle insertion.

2. The overall risk of having a baby with a chromosomal abnormality in the X or Y chromosomes is 0.8%, or 8 per 1000 (this risk is four times the average seen with spontaneous conception). At present, we do not know why there is this increased risk for children conceived through ICSI. It is important to understand that the following problems can be associated with sex chromosome abnormalities: increased risk of miscarriage; heart problems for affected infants that may require surgery; increased risk of behavior or learning disabilities with affected children; and increased risk of infertility in your children during their adulthood.

The risk of having a chromosomal abnormality like Down's Syndrome is not increased with ICSI but rather increases only with maternal age.

There have been several studies that have addressed the issue of developmental delays in children born of ICSI. There is no conclusive evidence that this is the case since the studies are all small and have conflicting findings with respect to this observation.

• Will all of our eggs be injected ?

When you decide to proceed with ICSI, we will make every effort to inject as many eggs as possible. It is important for you to understand that only eggs that are mature can be injected. Our IVF laboratory can easily tell if an egg is mature or immature. If an egg is not mature, we cannot inject it with a sperm. Although the immature eggs are incubated with sperm, the likelihood of fertilization is very low. On average, we are able to inject 75-80% of your eggs that are recovered.

• Are there any differences in embryo quality or pregnancy rates between ICSI and non-ICSI embryos ?

NO. There appears to be no difference in the overall embryo quality achieved with ICSI embryos when compared to non-ICSI embryos. Similarly, no difference in pregnancy rates have been shown between ICSI embryos and non-ICSI embryos. Although unproven, there is a belief among many infertility specialists that ICSI may increase embryo yield from a given number of eggs recovered. This belief has been the basis for the expanded role of ICSI for many patients.

• Should we give serious consideration to ICSI ?

If you have been told that there are abnormalities with any sperm test results, you should give serious consideration to ICSI. We recommend ICSI to all couples with any degree of sperm abnormalities because the risk of poor fertilization is relatively high without ICSI. If the male partner has had a vasectomy reversal, we also recommend ICSI regardless of the sperm quality because of the presence of sperm antibodies that may affect fertilization. The best correlation with in vitro fertilization is a test called a strict morphology semen analysis. This is a standard test used to determine if you used ICSI for your IVF cycle.

The decision to proceed with ICSI is particularly difficult if there is no prior evidence of male factor infertility. Some couples choose ICSI because they want to do everything possible to maximize fertilization. However, it is important to understand that for many couples with normal sperm parameters maximal fertilization can be achieved with standard insemination during IVF without the use of ICSI.

• Should we give serious consideration to Split ICSI ?

For those couples interested in knowing about their own fertilization capability (given our inability to predict those couples without male factor infertility who will have compromised fertilization using standard incubation with sperm), we offer Split ICSI. This option involves performing ICSI on a majority of all mature eggs and incubating the remainder with sperm. In effect, Split ICSI can provide a safety net against failed fertilization with standard insemination. The fee charged for Split ICSI is the same as ICSI. One requirement for Split ICSI is a minimum number of mature eggs. We must be able to identify at least 8 mature eggs on the day of your egg retrieval in order to proceed with Split ICSI. If this requirement is not met, then we will, by default, inject all of your mature eggs.

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