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IVF and ICSI
Intracytoplasmic sperm injection (ICSI) is a laboratory technique used with in vitro fertilizaton (IVF). The technique involves injecting a single living sperm directly into the center of woman's egg. "By using ICSI, we're doing everything we can to maximize the fertilization rate and embryo quality that develops," says Ed Marut, M.D., a fertility doctor and medical director of Fertility Centers of Illinois.
ICSI was first developed in the 1990s in order to help couples who had severe male factor infertility or who had failed to achieve fertilization in a previous attempt at IVF.
The ICSI Procedure.
In conventional IVF, after a woman's eggs are retrieved, they are left in a petri dish with sperm in order to achieve natural fertilization.
ICSI takes place in the IVF lab. Just like with conventional IVF, the female undergoes ovarian stimulation with fertility drugs, and her eggs are retrieved and incubated in the IVF lab. Then, the semen sample is prepared in the centrifuge — the sperm cells are spun through a special medium to separate live sperm from most of the dead sperm and debris. The embryologist then selects a single live sperm, which is injected directly into the egg with a small needle.
Who Should Use ICSI?
ICSI is most often used in cases of male factor infertility. The procedure can achieve fertilization when the man has low sperm count, or poor sperm morphology (shape) or motility (movement), or the sperm have trouble attaching to the egg. It can also be used when a blockage in the man's reproductive tract keeps the sperm from getting out, in which case a testicular biopsy is performed, and testicular sperm are used.
Patients may also choose to undergo ICSI when the male partner has variable sperm counts, there is unexplained infertility, or the couple has failed previous attempts at IVF. In fact, some fertility clinics use ICSI for all fertilizations.
"We started doing ICSI in the early 90s, and we first started doing it only in the situations where there was significant male factor," Dr. Marut says. "Then once we started learning how that was working, we found that men with severe male factor doing ICSI, they had better results than men who had normal sperm doing regular IVF. So we started moving the more normal semen quality to the ICSI side, and we found not only did we get a better result than with conventional IVF, but we also got better quality embryos and avoided the unexplained failed fertilization, where everything looked great — sperm looked great, eggs looked great — and nothing happens. Then it's too late. So we've been using ICSI for all couples since then."
Is ICSI Safe?
The same risks that are associated with IVF are associated with IVF and ICSI. In addition, ICSI has been linked to an increased risk for imprinting defects, a phenomenon in which certain genes function differently depending on whether they involve a particular chromosome passed on by the father or by the mother, such as Angelman's Syndrome. There is some evidence that the imprinting errors already exist in the parents and are not due to ICSI or embryo culture.
According to the American Society for Reproductive Medicine, certain conditions that have been associated with the use of ICSI, including Angelman's Syndrome, Beckwith-Wiedemann syndrome, hypospadias and sex chromosome abnormalities — are thought to occur in less than 1 percent of children conceived using the technique.