IVF vs IUI: What's the Difference and Which Is Right for You?

The core difference in 30 seconds

IUI (intrauterine insemination) places washed, concentrated sperm directly into the uterus around the time of ovulation. Fertilisation happens inside the body, the same way it does naturally — you're just giving the sperm a head start. IVF (in vitro fertilisation) removes eggs from the ovaries, fertilises them with sperm in a laboratory, grows the resulting embryos for 5 days, and transfers the best one back into the uterus. Fertilisation happens outside the body.

In simple terms: IUI assists natural conception. IVF bypasses it.

Success rates: how they compare

This is where the gap is significant. IUI success rates in the UK are around 10–15% per cycle for women under 35, dropping to 5–10% for women over 38. IVF success rates are around 30–40% per cycle for women under 35, and 15–25% for women aged 38–39. For women over 42, both treatments have low success rates, but IVF still outperforms IUI.

Those numbers need context though. IUI is a much simpler, less invasive treatment. Some couples do 3 to 6 IUI cycles before moving to IVF, and the cumulative success rate across multiple cycles can be meaningful — 3 IUI cycles at 12% each gives a roughly 30% cumulative chance, which isn't far from a single IVF cycle.

Cost: the biggest practical difference

A single IUI cycle costs between £700 and £1,600 at most UK clinics, including monitoring scans and the insemination procedure. Medication adds £200–£600 if you're doing a stimulated cycle rather than a natural one. A single IVF cycle costs between £3,500 and £12,000 all-in, including medication, monitoring, egg collection, embryology and embryo transfer.

So a single IVF cycle costs roughly 4 to 8 times more than a single IUI cycle. But because IVF has roughly 2 to 3 times the success rate, the cost per successful pregnancy is closer than the headline prices suggest. Three IUI cycles at £1,200 each (£3,600 total) with a cumulative 30% success rate gives a cost per pregnancy of roughly £12,000. One IVF cycle at £7,000 with a 35% success rate gives a cost per pregnancy of £20,000. IUI is still cheaper per success — but the gap narrows if you factor in the time, emotional cost and lost months.

What IUI involves: the procedure

An IUI cycle is straightforward. If it's unmedicated (natural cycle), the clinic monitors your natural ovulation with ultrasound scans and a blood test, then times the insemination to coincide with ovulation. If it's medicated, you take oral medication (usually letrozole or clomiphene) or low-dose injectable hormones to stimulate 1–2 follicles.

On insemination day, a sperm sample is collected (from a partner or donor), washed and concentrated in the lab, and then passed through a thin catheter directly into the uterus. The procedure takes about 5 minutes, feels similar to a smear test, and you go home immediately afterwards. There's no sedation, no egg collection, no embryology. It's a fundamentally simpler process.

When IUI makes sense

• Unexplained infertility where both partners' tests are relatively normal
• Mild male factor infertility (slightly low count or motility, but enough good sperm for IUI)
• Same-sex female couples or single women using donor sperm
• Ovulation disorders where medication alone isn't enough but IVF seems premature
• Couples who want to try a less invasive option before committing to IVF
• When the woman is under 35 with no tubal issues and the couple hasn't been trying long

When IVF is the better option

• Blocked or damaged fallopian tubes (IUI requires working tubes; IVF bypasses them entirely)
• Severe male factor infertility (very low sperm count or motility — ICSI is needed)
• Diminished ovarian reserve or advanced maternal age (time is a factor)
• Failed IUI cycles (most consultants recommend moving to IVF after 3–6 unsuccessful IUI attempts)
• Endometriosis, particularly moderate to severe
• Need for genetic testing of embryos (PGT-A or PGT-M)
• When using frozen eggs or embryos from a previous cycle

The emotional and physical difference

This is worth acknowledging because the data doesn't capture it. IUI is physically mild — a few scans, possibly some oral medication, and a quick procedure. Most people carry on with their normal routine throughout. IVF is more demanding: daily injections for 10–14 days, frequent clinic visits, a surgical egg collection under sedation, and the emotional weight of watching embryos develop in a lab. The two-week wait exists for both, but after IVF it tends to feel heavier because you've invested more — financially, physically and emotionally.

Some people find IUI's lower intensity easier to cope with, even if the per-cycle odds are lower. Others prefer to go straight to IVF because they want the highest possible chance per attempt and don't want to spend months on a treatment that might not work. There's no universally right answer — it depends on your diagnosis, your age, your finances and your tolerance for the process.

Can you get IUI or IVF on the NHS?

IUI is sometimes offered on the NHS as a first-line treatment, particularly for same-sex couples and single women using donor sperm. Availability varies by area. IVF on the NHS follows NICE guidelines — up to 3 cycles for women under 40, though most areas only fund 1. Eligibility criteria differ by Integrated Care Board (ICB), which is why it's often called the postcode lottery.

If you're paying privately, the cost difference makes IUI an attractive starting point. Three private IUI cycles cost less than one IVF cycle, and if IUI works, you've saved thousands and avoided a much more invasive procedure.

The decision framework

Ask your consultant three questions. First: given my specific diagnosis, what are the realistic success rates for IUI versus IVF? Second: how many IUI cycles would you recommend before switching to IVF? Third: is there any medical reason to go straight to IVF? If the answer to the third question is yes — blocked tubes, severe male factor, very low ovarian reserve — then IUI isn't the right path regardless of cost. If there's no clear medical barrier, IUI first is a reasonable strategy for many couples.

Compare clinics for both treatments

Whether you're exploring IUI or IVF, the choice of clinic matters. Pricing varies significantly — the same IUI cycle can cost £700 at one clinic and £1,500 at another in the same city. On Vero Fertility, you can compare UK clinics on both IVF and IUI pricing, HFEA-verified success rates, and what's included in the quoted price. It's the clearest way to understand your options before committing to a clinic or a treatment path.