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Intracytoplasmic Sperm Injection (ICSI) - risks of treatment

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The Private Healthcare UK guide to infertility treatment contains articles on infertility and IVF treatment which are aimed at improving your knowledge of treatments for infertility, their benefits and potential risks.


The guide is sponsored by The London Women's Clinic, leading fertility specialists who have been involved in fertility management since 1984.


The London Women's Clinic (LWC) delivers a full range of diagnostic and treatment programmes for fertility disorders  and operate one of the most successful IVF programmes in the world.


The LWC in Harley Street is rated in the top three amongst all UK licensed centres for women aged up to 35 and the HFEA has published the centre specific IVF success rates for the period 1st January – 30th June 2007 showing verified results of 55.7% success.


For more information about The London Women’s Clinic:


The London Women's Clinic London, Harley Street.

Tel: +44 (0) 20 7487 5050 E-mail:


In this section 



ICSI like IVF is an invasive procedure.  However, unlike IVF, ICSI involves injecting a sperm directly into an egg, therefore allowing the use of sperm that may not otherwise be able to fertilise an egg.  For these reasons, concerns about the potential risks to children born as a result of the ICSI have been raised, and several follow-up studies have been published.


The HFEA reviews the evidence on an ongoing basis.  ICSI is still a relatively new technique and all children conceived using ICSI are still very young.  Consequently, these follow-up studies involve relatively small numbers of children and do not include effects that may only be seen in older children or the next generation.  The HFEA considers follow-up studies to be extremely important and would encourage patients to talk to their treatment centre about participation in such studies.


Clearly, more studies are needed, but the use of ICSI has been potentially linked with certain genetic and developmental defects. 



    Possible inheritance of genetic and chromosomal abnormalities:


    Inheritance of cystic fibrosis gene mutations:  Some men who have no sperm in their semen are found to have congenital bilateral absence of the vas deference (CBAVD).  In this condition, the tubes that carry sperm from the testes to the penis are missing.  Two thirds of men with CBAVD are also carriers of certain cystic fibrosis mutations.  Men with CBAVD and their partners may therefore wish to undergo genetic testing before proceeding with ICSI.  Your treatment centre should be able to give you more information and counselling about the implications of genetic testing. 




    Sex chromosome defects and the inheritance of sub-fertility:  A small proportion of sub-fertile men have parts of the Y chromosome missing (deleted).  Certain genes on the Y chromosome have been shown to be involved in the production of sperm, and deletion of these genes may be responsible for some men having few or no sperm in their semen.   Consequently, using sperm with such deletions to create an embryo may result in the same type of sub-fertility being passed from father to son.




    Abnormal numbers or structures of chromosomes:  The sex chromosomes (X & Y) in particular may be associated with infertility in both men and women, and babies born from ICSI treatment may have a slightly increased risk of inheriting these abnormalities.  Studies have found that up to 3.3^% of fathers of ICSI babies have abnormal chromosomes.  It is estimated that up to 2.4% of the wider population have a chromosomal abnormality.




  • Novel chromosomal abnormalities

    The complexity of the process of egg and sperm production means that even if an individual possesses a normal number of chromosomes, their gametes could potentially have an abnormal number.  It is not possible to detect beforehand which eggs or sperm have chromosomal abnormalities, and gametes that might not have been able to participate in natural fertilisation could therefore be used in ICSI.  Babies born after ICSI have been reported to have new chromosomal abnormalities in up to 3% of cases.  The rate in the general population is around 0.6%.


  • Possible developmental and birth defects

    There is not yet any clear evidence whether ICSI results in higher rates of birth defects.  The number of babies reported to have major birth defects, such as cleft palate, is between one and five % in both the general population and in babies born following ICSI.  Studies suggest that minor abnormalities occur in up to 20% of ICSI babies, compared to up to 15% of the population.  For example, one recent study has shown a three fold excess risk in the rate of the relatively rate problem hypospadias following ICSI.  More studies are needed in order to gain further insight into these possible effects.



    Possible risks during pregnancy

    Miscarriage:  With ICSI it is possible that abnormal gametes, which would not usually be able to produce a viable embryo, could be used.  This may increase the chance of an abnormal embryo being formed.  However, most abnormal embryos will not implant into the womb and grow, but some might, leading to a possible higher risk of miscarriage.  It has been reported that the risk of miscarriage increases in proportion to the severity of male infertility.


    Medical and scientific information changes rapidly and the HFEA endeavours to keep patients and clinicians up to date with all relevant developments to help patients review their treatment options.

In this guide


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