Intrauterine insemination (IUI) is a minimally invasive and cost-effective form of assisted reproduction. Here, you’ll find out how the procedure works, what requirements are essential, what costs you might incur, and which factors affect success rates.
What is intrauterine insemination (IUI)?
During IUI, washed—that is, highly concentrated—sperm are introduced directly into the uterus via a fine catheter. This bypasses the cervical mucus, allowing the sperm to reach the egg more quickly. The method can be performed using partner or donor sperm (homologous or heterologous).
Common indications for IUI
- Slightly reduced sperm quality (count, motility).
- Irregular or absent ovulation in women.
- Cervical factor infertility (thick mucus, antisperm antibodies).
- Unexplained infertility despite regular intercourse.
- Single women or same-sex couples using donor sperm.
- Immunological causes (antisperm antibodies) with otherwise normal semen analysis.
Requirements for a successful IUI
- At least one patent fallopian tube (confirmed by HSG or HyCoSy).
- Confirmed ovulation—naturally or medically induced.
- Fertile sperm (> 5 million motile after preparation).
- No acute infection in the genital tract.
- Genetic screening for donor sperm to exclude hereditary conditions.
Step by step: How an IUI works
- Preliminary tests & counselling: cycle monitoring, semen analysis, blood tests and ultrasound checks.
- Mild ovarian stimulation: Clomiphene or low-dose gonadotropins to support 1–3 follicles.
- Ovulation trigger: hCG injection once the lead follicle reaches 17–20 mm.
- Sperm preparation: fresh or thawed sample is concentrated by swim-up or density gradient.
- Insemination: 24–36 hours after the hCG trigger, the sperm is injected into the uterus via catheter (procedure < 5 minutes, usually comfortable).
- Luteal support: vaginal progesterone to support the uterine lining.
- Pregnancy test: blood β-hCG check 14 days after insemination.
Advantages of IUI
- Direct placement of sperm—avoidance of cervical mucus barriers.
- Minimally invasive and no need for general anaesthetic.
- Less expensive than IVF or ICSI.
- Short treatment duration and fewer clinic visits.
Quick comparison of fertilisation methods
- ICI / IVI – Intracervical insemination
Semen is placed at the entrance to the cervix via syringe or cup. Suitable for mild fertility issues or donor sperm; lowest cost and maximum privacy. - IUI – Intrauterine insemination
Washed sperm are delivered directly into the uterus via catheter. Ideal for moderate male factors, cervical issues or unexplained infertility; clinically straightforward and mid-range cost. - IVF – In vitro fertilisation
Multiple stimulated eggs are fertilised in the lab with prepared sperm. Standard for blocked tubes, endometriosis or failed IUI; higher success rates and higher costs. - ICSI – Intracytoplasmic sperm injection
A single sperm is microinjected into an egg. Precision solution for severe male infertility or surgically retrieved sperm; highest cost but best chance when sperm quality is very low.
Success prospects: What are the chances with IUI?
The success rate per cycle varies by age:
- Under 35 years: 12–18 %.
- 35–40 years: 8–12 %.
- Over 40 years: around 5 % or less.
Three to six consecutive IUI cycles can raise cumulative success rates to around 30–45 % before considering a switch to IVF.
Tips for improving success
Optimise your lifestyle:
- Maintain a healthy BMI, stop smoking, limit alcohol intake.
- Manage stress through yoga, meditation or moderate exercise.
Sperm and cycle optimisation:
- Abstain for 2–3 days before providing a semen sample.
- Accurate cycle monitoring (ultrasound & LH tests) for optimal timing.
- Use fertility-friendly lubricant during intercourse in the stimulation phase.
Risks & safety
Medication risks:
- Ovarian hyperstimulation syndrome (OHSS) – rare with low-dose protocols.
- Multiple pregnancy risk (5–10 %) if more than one follicle releases an egg.
Procedure-related risks:
- Mild cramping or light bleeding after catheter insertion.
- Rare uterine infections (reduced by aseptic technique).
Emotional impact: Repeated negative tests can be distressing—consider psychosocial support or counselling.
Costs & NHS funding
In the UK, private clinics typically charge between £800 and £2,000 per IUI cycle, depending on the services included. The NHS may fund up to three cycles for eligible couples under local Clinical Commissioning Group (CCG) guidelines and specific eligibility criteria (age, BMI, prior treatments). Private health insurance may also contribute—check your policy.
When to consider the next step?
- Under 35 years: after three to four unsuccessful IUI cycles.
- 35–40 years: after three cycles without success.
- Over 40 years or significantly reduced sperm quality: consider IVF or ICSI early.
Your clinic will advise on the optimal timing for a treatment change or additional tests.
Scientific sources & guidelines
Conclusion
Intrauterine insemination offers couples, single women and same-sex couples a realistic chance of pregnancy with moderate cost and stress. With careful cycle monitoring, appropriate stimulation and professional support, IUI can be the key step towards parenthood before moving on to more invasive treatments such as IVF or ICSI.