Intracytoplasmic
Sperm Injection (ICSI)
There
is a male contributing factor in approximately 47% of
infertile couples. In the past, couples with moderate
to severe male factor infertility had to use a donor's
sperm. In vitro fertilization combined with ICSI has enabled
thousands of sub fertile men to father their own, genetically
related, children.
ICSI
is performed in conjunction with an IVF cycle. In an
IVF cycle, the female undergoes ovulation induction
with follicle stimulating hormone. These medications
cause her ovaries to produce numerous eggs that can
be used in assisted reproductive technology procedures.
Once her eggs are mature she is given an injection of
hcG, or LH, and scheduled for egg retrieval.
The
male partner arrives at the clinic on the day of egg
retrieval and provides sperm by masturbation. This assumes
that he has an acceptable quantity of quality sperm.
If sufficient sperm are not available, intracytoplasmic
sperm injection will be employed.
If
his ejaculate is to be used for ICSI, there must be
enough viable sperm so that one can be aspirated and
injected into the egg. If there is not enough sperm,
it can usually be obtained from the male reproductive
tract. Sometimes there are no viable sperm present in
the ejaculate.
When
no sperm are available in the ejaculate, (or in the
case of a previous vasectomy) procedures such as testicular
sperm aspiration can be employed. In this procedure,
sperm are withdrawn directly from the testicles. Sperm
can also be obtained using microsurgical epidermal sperm
aspiration, where they are withdrawn from the male reproductive
tract or epididymis.
Once
the sperm is aspirated into the needle, it is inserted
through the egg membrane (zona pellucida). Once inside
the egg, the sperm can cause fertilization, and a puncture
does not damage the egg. The fertilized eggs or embryos
are then incubated until mature at which point they
will be transferred to the mother's uterus.
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