Treatment Overview
Intracytoplasmic sperm injection (ICSI) is an
assisted reproductive technology (ART) used to treat
sperm-related infertility problems. ICSI is used to enhance the fertilization
phase of
in vitro fertilization (IVF) by injecting a single
sperm into a mature egg. The fertilized egg is then placed in a woman's
uterus or
fallopian tube.
Sperm
collection. If sperm cannot be collected by means of masturbation, they
are surgically removed from a
testicle through a small incision. This method of
sperm retrieval is done when there is a blockage that prevents sperm from being
ejaculated or when there is a problem with sperm development. To screen for
possible genetic problems that could affect offspring, experts recommend that
men with little or no sperm in their semen (not due to a blockage) have genetic
testing before they proceed with ICSI.1
Ovulation and egg retrieval. To prepare for an
assisted reproductive procedure using your own eggs, you must get daily
injections and be closely monitored for 2 weeks before egg retrieval. At home,
you or your partner injects you with gonadotropin or
follicle-stimulating hormone (FSH) to stimulate your
ovaries to produce multiple eggs (superovulation). After the first week,
your doctor checks your blood estrogen levels and uses
ultrasound to see whether eggs are maturing in the
follicles. During the second week, your dosage may
change based on test results and ultrasound. If follicles fully develop, you
are given a human chorionic gonadotropin (hCG) injection to stimulate the
follicles to mature. The mature eggs are collected 34 to 36 hours later using
laparoscopy or needle aspiration guided by ultrasound
through the abdomen to the ovaries.
Sperm
injection and transfer. Under high-power magnification, a glass tool
(holding pipet) is used to hold an egg in place. A microscopic glass tube
containing sperm (injection pipet) is used to penetrate and deposit one sperm
into the egg. After culturing in the laboratory overnight, eggs are checked for
evidence of fertilization. After incubation, the eggs that have been
successfully fertilized (zygotes) or have had 3 to 5 days to further develop
(zygotes or blastocysts) are selected. Two to four are placed in the uterus
using a thin flexible tube (catheter) that is inserted through the cervix. The
remaining embryos may be frozen (cryopreserved) for future attempts.
What To Expect After Treatment
Overall, in vitro fertilization
(IVF)-related injections, monitoring, and procedures are emotionally and
physically demanding of the woman.
Superovulation with hormones requires regular blood
tests, daily injections (some are quite painful), and frequent monitoring by
your doctor.
These procedures are done on an outpatient basis and
require only a short recovery time. Your doctor may advise you to avoid
strenuous activities for the remainder of the day.
Why It Is Done
Intracytoplasmic sperm injection
(ICSI) is used to treat severe male infertility, as when little or no sperm are
ejaculated in the semen. Immature sperm collected from the testicles are
usually unable to move about and are more likely to fertilize an egg through
ICSI.
Some couples choose to try ICSI after repeat in vitro
fertilization has been unsuccessful. In the United States, about half of IVF
procedures are currently performed using ICSI technology.2
ICSI is also used for couples who are planning
to have genetic testing of the embryo to check for certain
genetic disorders. ICSI uses only one sperm for each
egg, so there is no chance the genetic test can be contaminated by other
sperm.
How Well It Works
Used with in vitro fertilization and
eggs of good quality, ICSI often is a successful treatment for men with
impaired or no sperm in the ejaculate. ICSI (using sperm collected from the
testicles) produces an estimated 25% to 30% birth rate.3
ICSI does not improve the chances of conception
for men with good-quality sperm in the ejaculate.4
Risks
Risks related to ICSI are the same as for in
vitro fertilization, which increases the risks of ovarian hyperstimulation
syndrome and multiple pregnancy.
- Superovulation with hormone treatment
can cause
severe ovarian hyperstimulation syndrome, occurring in
0.5% to 2% of all IVF treatment cycles.4 Your doctor
can minimize the risk of ovarian hyperstimulation syndrome by closely
monitoring your ovaries and hormone levels during
treatment.
- Approximately 35% of births in the United States that
result from assisted reproductive technologies such as IVF produce pregnancies
with twins or more.5Multiple pregnancies are high-risk for both a mother
and her fetuses.
Possible birth defect risks. ICSI is
a relatively new ART procedure that has recently raised concerns about
increased birth defect rates. While some studies have found no differences
between ICSI and non-ICSI babies, a large, multicenter study has recently
identified higher rates of certain birth defects in ICSI babies. In this study,
newborns as well as fetuses that were not liveborn were examined. Overall,
major problems that impact quality of life and need medical attention affected
8.6% of ICSI babies versus 6.9% of babies conceived naturally. The most common
problems were heart and internal urinary/genital defects. Heart defects
affected 2.1% of ICSI babies and 1.1% of non-ICSI babies. Internal
urinary/genital defects affected 2.5% of ICSI and 1.6% of non-ICSI
babies.6
Current research differs on
whether ICSI-conceived children score lower on cognitive tests than other
children. One study comparing naturally conceived and ICSI children between 1
and 2 years of age challenges earlier studies that found cause for concern.
This study of over 500 children has found no differences in mental ability, nor
in birth defects, between naturally conceived children and ICSI-conceived
children.7 But larger and longer-term studies are
necessary to prove that ICSI babies have no increased risks.
Treatment success versus the risk of multiple pregnancy
In order for a woman over age 35 to maximize her chances of conceiving
with her own eggs and carrying a healthy pregnancy, she must have more embryos
transferred than do younger women. This practice, though, increases her risk of
conceiving multiple fetuses.
Because of the risks of multiple
pregnancy to the babies, the American Society for Reproductive Medicine
recommends that women under age 35 have no more than two embryos transferred,
women age 35 to 37 have no more than three, women 38 to 40 have no more than
four transferred, and women who have had repeated failed cycles or are over age
40 have no more than five embryos transferred.8
Women over 40 have a high rate of embryo loss when they use their own
eggs. As an alternative, older women can choose to use more viable donor
eggs.
What To Think About
Doctors advise men who have little
or no sperm in their semen (not due to a blockage) to have genetic testing
before ICSI.1 Intracytoplasmic
sperm injection is an effective treatment for sperm-related infertility, but it
may carry genetic risks. Couples diagnosed with a chromosomal problem can seek
genetic counseling to learn their potential for having a child with birth
defects.
If you and your doctor are concerned about passing on a
genetic disorder to your child, talk to your doctor about preimplantation
genetic diagnosis. Some genetic disorders can be identified with specialized
testing before an embryo is transferred.
Frozen IVF embryos that
are thawed and transferred to the uterus are less likely to result in a live
birth (29% success) than are newly fertilized IVF embryos (50%
success).2 But frozen embryos are less expensive and
less invasive for a woman, because superovulation and egg retrieval aren't
necessary.
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