Overview
Intracytoplasmic sperm injection (ICSI) is a laboratory technique used within an IVF cycle. Everything before and after it is the same as IVF: hormone stimulation, egg collection, embryo culture and embryo transfer. The difference lies in how fertilisation happens. In conventional IVF, each egg is placed in a dish with many thousands of prepared sperm and fertilisation is left to happen naturally. In ICSI, an embryologist picks a single sperm, draws it into a very fine glass needle and injects it into the centre of a mature egg.
ICSI was developed for sperm problems, and that remains its main purpose. The UK regulator, the HFEA, says it may be recommended where the sperm count is very low, where sperm move poorly or are abnormally shaped, where sperm has to be collected surgically, or where few or no eggs fertilised in a previous IVF cycle. It is also used when embryos are to be genetically tested, so that stray sperm stuck to the outside of an egg cannot affect the result.
Many clinics, in Thailand and elsewhere, now use ICSI for most or all cycles. The evidence does not support this for couples without a sperm problem: the HFEA says there is no scientific evidence that ICSI helps where infertility is unrelated to sperm, and ESHRE's 2023 good practice recommendations state that ICSI is not recommended for non-male factor infertility. Ask your clinic why it is suggesting ICSI in your case.
Who it's for
- Couples where the male partner has a very low sperm count, or sperm with poor movement or abnormal shape.
- Men whose sperm is collected surgically from the testicle or epididymis, for example after a vasectomy or because of a blockage.
- Couples whose eggs fertilised poorly, or not at all, in a previous conventional IVF cycle.
- Cycles using frozen sperm of limited quality, or eggs that have been frozen and thawed (thawed eggs are fertilised by ICSI).
- Cycles where embryos will have preimplantation genetic testing.
Whether a treatment suits you depends on your own history and tests — discuss it with a fertility specialist.
Step by step
Assessment, including a semen analysis
Both partners are assessed as for IVF. A semen analysis, sometimes repeated, shows the count, movement and shape of the sperm and helps the clinic decide between conventional IVF and ICSI. Where there is a severe sperm problem, genetic tests and counselling may be offered first.
Ovarian stimulation and monitoring
Daily hormone injections over roughly ten to fourteen days encourage several eggs to mature. Scans and blood tests track the follicles and guide the dose, exactly as in IVF.
Egg collection and sperm sample
Eggs are collected under sedation or anaesthesia using a fine needle guided by ultrasound. On the same day the male partner provides a sample, or a frozen or surgically retrieved sample is prepared.
Preparing the eggs
The cells surrounding each egg are removed so the embryologist can see whether it is mature. Only mature eggs can be injected; immature eggs are usually not used.
Sperm injection
Under a high-powered microscope, the embryologist holds each mature egg steady, picks a single moving sperm and injects it into the egg with a very fine needle.
Fertilisation check and embryo culture
The next day the clinic checks how many eggs have fertilised. Embryos are then cultured for several days, often to the blastocyst stage at around day five, and suitable spare embryos can be frozen.
Embryo transfer and pregnancy test
An embryo is transferred to the womb through a thin catheter, either in the same cycle or later as a frozen embryo transfer. A pregnancy test follows about two weeks later.
Typical timeline
- Tests and consultation
- Usually 1–4 weeks before starting
- Ovarian stimulation
- About 10–14 days
- Egg collection and injection
- Same day
- Fertilisation check to transfer
- About 2–5 days
- Transfer to pregnancy test
- About 2 weeks
- Whole cycle
- Similar to IVF: typically 3–6 weeks from the start of medication
What it costs
ICSI is either built into an IVF package or added as a separate charge. Some Thai clinics publish packages that include it: MedPark's IVF/ICSI package (280,000 baht, Thai nationals and residents only) lists ICSI among its inclusions, and Beyond IVF publishes an ICSI package from 175,000 baht that excludes embryo freezing, thawing and chromosome testing. Check whether ICSI is included in each quote you compare, and ask why it is being recommended for you.
Risks and side effects
- The usual risks of IVF apply, including ovarian hyperstimulation syndrome, multiple pregnancy if more than one embryo is transferred, ectopic pregnancy and the small risks of egg collection.
- Handling and injecting eggs can occasionally damage them, so a few eggs may not survive the procedure.
- A very small number of children born after ICSI have genetic or developmental problems. The HFEA notes these may be linked to the underlying fertility problem rather than to ICSI itself, and that suggested links to long-term health problems are unproven either way.
- Where male infertility has a genetic cause, particularly on the Y chromosome, sons conceived through ICSI are likely to inherit it. Genetic testing and counselling beforehand may be suggested.
- Using ICSI when there is no sperm problem adds cost without clear evidence of benefit.
Questions to ask a clinic
- Why are you recommending ICSI rather than conventional IVF for us?
- Do you use ICSI for every patient, or only where there is a sperm problem?
- Is ICSI included in the package price, or charged separately?
- Should we have genetic tests or counselling before treatment because of the sperm results?
- What proportion of injected eggs usually fertilise in your laboratory?
- What happens if sperm cannot be found on the day of egg collection?
Frequently asked questions
Does ICSI have better success rates than IVF?
Not in general. The HFEA says ICSI success rates are very similar to IVF, which is why it does not publish them separately. Success depends mainly on the age of the person providing the eggs and the cause of infertility.
Is ICSI worth it if there is no sperm problem?
Current evidence suggests not. The HFEA says there is no scientific evidence that ICSI helps where infertility is unrelated to sperm, and ESHRE does not recommend it for non-male factor infertility. Discuss your own situation with a fertility specialist.
Is ICSI safe for the baby?
Most babies born after ICSI are healthy. A very small number have genetic or developmental problems, which may relate to the underlying infertility rather than the technique. If male infertility has a genetic cause, a son may inherit it.
Does ICSI feel any different from IVF for the patient?
No. The injection happens in the laboratory, so the medication, scans, egg collection and embryo transfer are the same as in IVF.
Can ICSI be used with surgically retrieved sperm?
Yes. Sperm retrieved from the testicle or epididymis is usually too few in number for conventional IVF, so ICSI is used. Ask the clinic whether retrieval is done on the day of egg collection or in advance, with the sperm frozen.
