Intracytoplasmic sperm injection (ICSI) is a laboratory technique used as part of IVF. Instead of letting sperm find the egg, an embryologist injects a single sperm directly into the inside of each mature egg. Everything else in the IVF cycle stays the same.
What ICSI is
In standard IVF, eggs and many sperm are placed together and fertilisation happens on its own. In ICSI, a single sperm is picked up with a very fine needle and injected into the centre of the egg.
This helps when sperm cannot get through the outer layer of the egg by themselves. ICSI does not replace the other steps of IVF: stimulation, egg collection and embryo transfer are unchanged.
ICSI is widely used. Cleveland Clinic reports that about 6 in 10 IVF procedures now include ICSI, and that ICSI success rates are similar to traditional IVF.
Think of ICSI as a lab helper for fertilisation only. It does not change how eggs are grown, collected or transferred, and it cannot improve egg quality.
Who it is for
- Very low sperm count
- Sperm that move poorly or are abnormally shaped
- Previous IVF cycles where eggs did not fertilise
- Sperm collected surgically, for example after vasectomy or a blockage
- Frozen sperm or frozen eggs
- When embryos will have genetic testing (PGT)
- Problems with ejaculation, such as retrograde ejaculation, where semen flows back into the bladder
- A blockage in the male reproductive tract
Success rates for ICSI are generally similar to IVF. Your doctor will advise whether ICSI is needed based on semen tests and your history.
ICSI is not helpful for everyone. The HFEA says there is no scientific evidence that ICSI helps when infertility is not related to sperm, and using it without a reason may add cost without improving your chances.
Step by step
- Stimulation and egg collectionExactly as in IVF: hormone injections for about 8 to 14 days, then eggs are collected under sedation.
- Sperm preparationA semen sample, or surgically collected sperm, is prepared in the lab.
- Holding the eggUnder a microscope, a holding pipette, a small glass tube with gentle suction, keeps the mature egg still.
- Injecting one spermOne sperm is immobilised and picked up in a thin needle, which is passed into the egg to release the sperm into the cytoplasm.
- Checking fertilisationThe next day, the embryologist checks which eggs have fertilised. Embryos are then cultured as in IVF.
- Transfer and testAn embryo is usually transferred on day 5 or 6, with a pregnancy test about two weeks later.
Fertilisation is not guaranteed. Cleveland Clinic reports that 50% to 80% of ICSI attempts result in fertilisation. The embryologist checks the next day which eggs have fertilised.
What it feels like
You will not feel the ICSI step itself because it happens in the laboratory. Your experience is the same as an IVF cycle: injections, monitoring scans, egg collection under sedation, and a simple embryo transfer without anaesthetic.
- Stimulation: hormone injections at home for about 8 to 14 days, with scans and blood tests.
- Egg collection: under sedation, with mild soreness afterwards for some people; no driving for 24 hours.
- Waiting: at least two weeks between transfer and the pregnancy test.
For the male partner, giving a sample is usually the only step. If sperm must be collected surgically, ask about recovery time separately.
How to prepare
- Have a semen analysis so your doctor can judge whether ICSI is needed
- Ask whether genetic counselling is advised, especially for very low sperm counts
- Follow the abstinence advice your clinic gives before the sample
- Do not assume ICSI guarantees fertilisation
- Do not stop prescribed medicines without asking
- Abstain from ejaculation for about 2 to 3 days before giving the sample, or as your clinic advises
- If the sample is collected at home, it usually needs to reach the lab within 60 minutes
- Ask whether frozen or surgically collected sperm will be used, and plan for that step
Risks and side effects
| Risk | What sources say |
|---|---|
| Egg damage | Some or all eggs may be damaged by the injection. |
| Birth defects | Natural-conception rate is about 1.5% to 3%; ICSI-linked conditions affect less than 1% of children, partly due to the underlying infertility. |
| Inherited male infertility | Sons may inherit their father's fertility problem, especially with Y-chromosome causes. |
| General IVF risks | OHSS, multiple pregnancy and ectopic pregnancy still apply. |
Even after a successful injection, some eggs do not fertilise, and some embryos stop developing in the lab. Standard IVF risks, such as OHSS and multiple pregnancy, still apply to the rest of the cycle.
Sources note that the slightly higher risk in children may partly reflect the parents' underlying infertility rather than the injection itself. Researchers are still studying this.
ICSI cannot fix every sperm problem. Ask your doctor about the cause of the male factor before treatment.
How DBN does it
- IVF & ICSI is about 450,000 THB per cycle including blastocyst culture, over 4–6 weeks.
- Embryos are cultured to day 5 (blastocyst), and one embryo is transferred at a time to reduce twin risk.
- First consultation is free; prices are confirmed at consultation.
When to see a doctor
- A semen analysis showed a low count, poor movement or abnormal shape
- No sperm were found in the ejaculate
- A previous IVF cycle had little or no fertilisation
- You have had a vasectomy and want children
Questions & answers
Is ICSI better than IVF?
Not necessarily. It helps when sperm need assistance, and success rates are generally similar to IVF.
Does ICSI hurt?
No. The injection is done to the egg in the lab, so you feel only the usual IVF steps.
Can all eggs be injected?
Only mature eggs are suitable for ICSI, so the number injected may be lower than the number collected.
Related DBN services
Related articles
Sources
- Intracytoplasmic sperm injection (ICSI) — HFEA
- Intracytoplasmic sperm injection (ICSI) patient education fact sheet — ASRM / ReproductiveFacts.org
- Intracytoplasmic Sperm Injection (ICSI) — Cleveland Clinic
- IVF: What are the risks? — ASRM / ReproductiveFacts.org