Intracytoplasmic Sperm Injection

Intracytoplasmic sperm injection, or ICSI, is a technique developed to help achieve fertilization for couples with severe male factor infertility or couples who have had failure to fertilize in a previous in vitro fertilization attempt. The procedure overcomes many of the barriers to fertilization and allows couples with little hope of achieving successful pregnancy to obtain fertilized embryos. The procedure was first used at UCSF in 1994 and our first successful birth, achieved with ICSI assistance, was in February 1995. UCSF was the first San Francisco Bay Area program to achieve a pregnancy and birth with this procedure. 

How ICSI Works 

The technique involves very precise maneuvers to pick up a single live sperm and inject it directly into the center of a human egg. The procedure requires that the female partner undergo ovarian stimulation with fertility medications so that several mature eggs develop (IVF). These eggs are then aspirated through the vagina, using vaginal ultrasound, and incubated under precise conditions in the embryology laboratory. The semen sample is prepared by centrifuging (spinning the sperm cells through a special medium). This solution separates live sperm from debris and most of the dead sperm. The embryologist picks up the single live sperm in a glass needle and injects it directly into the egg. Click here to see a video of ICSI from our lab.

ICSI is considered absolutely necessary in the case of male factor infertility with an abnormal semen analysis. In the Bay Area, however approximately 75% of all IVF cases are now ICSI. Patients are electing to undergo ICSI for reasons other than male factor infertility. Those reasons include previous poor fertilization with IVF, variable sperm counts, and unexplained infertility. Thus, many patients choose to undergo the ICSI procedure to maximize their success even when the procedure may not be clearly indicated. Through the ICSI procedure, many couples with difficult male factor infertility problems have achieved pregnancy at UCSF. Fertilization rates of 70-80% (of all eggs injected) equivalent to that of fertilization with normal sperm are currently being achieved, and pregnancy rates are comparable to those seen with IVF in couples with no male factor infertility. The most important indicator of ICSI success appears to be the fertilization rate achieved with the ICSI procedure. The fertilization rate using our ICSI technique in the UCSF IVF laboratory is exceptional (currently 80-85%). That is to say, on average for every ten eggs, 8 eggs will fertilize normally.