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Intracytoplasmic sperm injection

Kathleen Miller, DHSC
Section Editor
Robert L Barbieri, MD
Deputy Editor
Kristen Eckler, MD, FACOG


Intracytoplasmic sperm injection (ICSI) refers to a technique in which a single sperm is injected directly into the cytoplasm of a mature oocyte. This procedure is performed as part of an in vitro fertilization (IVF) cycle, and provides an effective method for assisting fertilization in men with suboptimal semen parameters or who experienced no or low fertilization rates after conventional IVF.

ICSI was first applied to human gametes in 1988 [1]; it was first used in cases of fertilization failure after standard IVF or when few sperm cells were available. The first pregnancies were reported in Belgium in 1992 [2]. This technique has consistently demonstrated higher fertilization rates than prior micromanipulation techniques, and produced more embryos with higher implantation rates [2-5]. The capacity of ICSI to permit almost any type of spermatozoa to fertilize oocytes has made it the most successful treatment for male factor infertility. In 2008, IVF with ICSI comprised 64.3 percent of ART procedures in the United States, IVF without ICSI comprised 35.5 percent; GIFT, ZIFT, or a combination of procedures accounted for the remainder [6]. The use of ICSI in the United States has increased dramatically since 1995, without a proportionate increase in diagnosis of male-factor infertility [7]. The use of ICSI for male factor infertility increased from 84 percent in 2003 to 93 percent in 2012 [8,9]. Worldwide, there is geographic variation in the use of ICSI with IVF [10].

This topic discusses the indications, techniques, and outcomes for ICSI. Other treatments for male infertility are discussed elsewhere. (See "Treatments for male infertility".)


A thorough evaluation of the male patient, including semen analysis [11,12], sperm morphology [13], and urology consultation is warranted. Although controversial, some authorities also utilize additional tests such as sperm antibody testing [14], and a wide spectrum of spermatozoa function tests ranging from, but not limited to, hamster-spermatozoa penetration assay, hemi-zona assay, mannose binding assay, hypo-osmotic swelling test, and acrosome reaction assay [15-20] for identifying couples at risk for reduced or no fertilization with conventional IVF [13,21-25]. In males with severe oligospermia or azoospermia, additional testing may be recommended. (See "Approach to the male with infertility".)

The most common genetic factors associated with male infertility are cystic fibrosis gene mutations (associated with congenital absence of the vas deferens), structural chromosomal abnormalities (eg, aneuploidy, inversion, translocation) associated with impaired testicular function, and Y chromosome microdeletions (associated with impaired spermatogenesis). Cystic fibrosis is associated with a mutation of the cystic fibrosis transmembrane conductance regulator gene. Men who carry this gene may not have the classic clinical manifestations of cystic fibrosis. (See "Causes of male infertility", section on 'Sperm transport disorders'.)

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Literature review current through: Nov 2017. | This topic last updated: May 09, 2017.
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