ICSI Step by Step From Day One, and How Age Affects Success
The steps of ICSI from ovarian stimulation to embryo transfer, and how the wife's age affects the chances of success.
ICSI and IVF
Eggs are fertilized in the lab and the best embryos are transferred to the uterus. In ICSI, a single selected sperm is injected into each mature egg: the method of choice for severe male factor and previous fertilization failure.
In vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) are among the most widely used assisted reproduction techniques in the world. In IVF, eggs and sperm are placed together in a lab dish and fertilization happens on its own. In ICSI, an embryologist selects a single sperm and injects it directly into a mature egg under a high-magnification microscope.
When is ICSI the right choice?
- Severely low sperm count, motility or morphology, or sperm that has to be retrieved surgically from the testis.
- Blocked or damaged fallopian tubes.
- Fertilization failure in a previous IVF attempt.
- Unexplained infertility after simpler treatments have not worked.
- Embryos that need genetic testing before transfer.
The steps
- Assessment first: hormone tests and ovarian reserve (AMH), a transvaginal ultrasound to count the follicles, and a semen analysis.
- Ovarian stimulation: hormone injections for about 10 to 12 days, with a protocol chosen by age and ovarian reserve, monitored by ultrasound and blood tests.
- Trigger shot: completes the maturation of the eggs, given about 36 hours before retrieval.
- Egg retrieval: a fine needle guided by ultrasound, through the vagina, under light anesthesia.
- Injection and lab culture: the embryos are checked every day until day 3 or the blastocyst stage (day 5).
- Embryo transfer: usually one or two embryos depending on age and embryo quality. Good extra embryos are frozen.
- Pregnancy test: about two weeks after the transfer.
What is new in the field?
- Culturing embryos to day 5 to choose the embryos most able to implant.
- Vitrification (fast freezing), which preserves embryos very efficiently and allows a later transfer in a cycle where the uterus is better prepared.
- Single embryo transfer when the case allows it, to lower the risks of a multiple pregnancy for the mother and the babies.
- Personalized stimulation protocols that lower the risk of ovarian hyperstimulation.
What affects the chances of success?
The most important factor is the woman's age and egg quality, then sperm quality, the health of the uterus and its lining, and lifestyle, such as weight and smoking. That is why the plan is made after a full assessment of both partners, not one plan for everyone.
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