Short answer: IVF has a higher chance of a baby per cycle than IUI. IUI is simpler, cheaper, less invasive, and for some situations it is the right thing to try first. As of 2026, UK guidance recommends considering IUI with stimulation before IVF for unexplained infertility — a change from the guidance that stood for the previous thirteen years.
Which one is right for you depends less on the success rates than on why you are not conceiving. That is the part worth getting straight before you compare numbers.
Intrauterine insemination. Sperm — your partner’s or a donor’s — is prepared in the laboratory to concentrate the healthiest, most motile sperm, and then placed directly into the womb through a fine catheter at the point in your cycle when an egg is released.
It is quick, it does not need sedation, it feels much like a smear test, and fertilisation happens inside your body exactly as it would naturally. It can be done on your natural cycle, or with mild drugs to stimulate ovulation.
For IUI to have a realistic chance, you need at least one open, healthy fallopian tube, you need to be ovulating, and there needs to be enough motile sperm in the prepared sample. If your tubes are blocked, IUI cannot work — the sperm and egg have no route to each other.
In vitro fertilisation. Your ovaries are stimulated to produce several eggs, the eggs are collected under sedation, and fertilisation happens in the laboratory. The resulting embryos are grown for a few days, and one is usually transferred back into the womb, with any others frozen.
IVF bypasses the tubes entirely, which is why it works when IUI cannot. It can be combined with ICSI, where a single sperm is injected directly into an egg, for significant male factor problems.
Two honest comparisons, and they point in slightly different directions.
The largest UK comparison analysed the HFEA national register for 2012 to 2016 — 319,105 IVF and ICSI cycles and 30,669 IUI cycles. Published in BMJ Open in 2020, it found that “IVF LB/cycle success was significantly better than IUI at 26.96% versus 11.49%”, while noting that “the IUI success is much closer to IVF at 2.35:1, than previously considered”.
The HFEA puts the same relationship in rounder terms on its own IUI page: “Success rates for IUI are generally around a third of that for IVF.”
For current IVF outcomes, the HFEA’s most recent published figures cover 2024. The average IVF birth rate per embryo transferred, using the patient’s own eggs, was 30% — 38% for patients aged 18 to 34, 31% at 35 to 37, 24% at 38 to 39, 16% at 40 to 42 and 8% at 43 to 44. Two caveats the HFEA states itself and we will repeat: the 2024 figures are preliminary and have not been validated, and because they now combine fresh and frozen transfers by age at egg collection, “these numbers are not directly comparable to previous reports”.
The per-cycle gap narrows considerably once you compare like with like. An individual participant data meta-analysis published in Human Reproduction Update in 2024, pooling four randomised trials and 908 women with unexplained infertility, compared IVF against IUI with ovarian stimulation. Live birth was 50.3% with IVF versus 43.2% with stimulated IUI, a hazard ratio of 1.19 with a confidence interval of 0.81 to 1.74. The authors concluded that “there is no significant difference in effectiveness or safety outcomes when undergoing IVF compared to IUI-OS”.
That finding is the reason the guidance changed.
Worth knowing, because “just keep trying” is sometimes offered as an alternative. In a randomised trial reported in the Lancet in 2018, 201 couples with three to four years of unexplained infertility were assigned to either three cycles of IUI or expectant management. Live birth was 31% with IUI and 9% with expectant management — a three-fold difference.
NICE guideline NG257 replaced the long-standing CG156 in March 2026, and it changed the IUI position materially.
For unexplained infertility. After two years of trying, NG257 recommendation 1.38.3 says to discuss the options and then either “consider up to 4 cycles of intrauterine insemination (IUI) with ovarian stimulation using gonadotrophins, or offer IVF treatment”. Under the previous guideline, stimulated IUI was not recommended for unexplained infertility at all. If you were told a few years ago that IUI was not worth trying in your situation, that advice may now be out of date.
It also says clearly what not to do: “Do not offer ovarian stimulation as a stand-alone treatment for unexplained fertility problems.” Drugs without insemination is not a treatment.
Where you cannot have intercourse, or need donor sperm. Recommendation 1.37.1 says to offer 12 cycles of unstimulated IUI before considering IVF for people who cannot, or would find it very difficult to, have vaginal intercourse because of a physical disability or psychosexual problem, and for couples where the male partner has azoospermia and surgical sperm retrieval is unsuitable or has failed.
Using donor sperm. Recommendation 1.37.2 says that if you have not conceived after six cycles of donor insemination, you should be offered a further 6 cycles of unstimulated donor IUI before considering IVF, provided there is no known clinical cause of infertility.
Skip IUI and go to IVF if:
Per cycle, IUI is much cheaper. At Veya:
The more useful question is the cost per baby, not per cycle, and here the answer is less obvious than it looks. The BMJ Open analysis of the UK register concluded that IUI was “more cost-effective in delivering 1 LB, and associated with lower risk of complications for maternal and neonatal complications”, and that “it is prudent to offer IUI before IVF nationally”.
That is a national-level conclusion, not a personal one. If your tubes are blocked, no amount of cost-effectiveness makes IUI a good buy. But if IUI is genuinely an option for you, it deserves a proper hearing rather than being skipped past.
Eligibility is set by your local Integrated Care Board and varies considerably by area, but NG257 sets the national benchmark. IVF is recommended for those who have not yet reached their 42nd birthday and meet the access criteria — which include not having conceived after two years of trying, with or without IUI. Under 40, that means an initial three full cycles, with up to three further cycles now to be considered if those do not work. At 40 or 41, with no previous IVF, one full cycle.
Your GP is the place to start, and it is worth doing before paying privately.
We are not going to tell you IUI is a stepping stone you have to walk across, and we are not going to tell you IVF is the only serious option. Both are things clinics say for reasons that have more to do with their own economics than with your situation.
What determines the answer is your tubes, your partner’s semen analysis, your ovarian reserve, your age and how much time you have. We will look at all five and tell you which we would choose, and why, and if the honest answer is that you should not be paying us for IUI, we will say that.
Most people describe mild cramping, similar to a smear test, lasting a few minutes. No sedation is needed and you can go back to your day afterwards.
It depends on the reason. For unexplained infertility with stimulation, NG257 says consider up to four cycles. For donor insemination it is six unstimulated cycles, and for people who cannot have intercourse it is twelve. If nothing has happened by the end of the recommended course, that is the point to reconsider rather than keep going.
Generally yes, and the HFEA says so: “you’re also more likely to get pregnant if you have fertility drugs to stimulate your natural cycle.” The trade-off is a higher chance of twins, which carries real risks for you and for the babies, so stimulated cycles need monitoring.
Yes. Donor sperm is always frozen and quarantined before use, and IUI with donor sperm is one of the most common routes for single women and same-sex female couples.
Unstimulated IUI does not meaningfully change it. Stimulated IUI does, because more than one egg may be released. That is one of the things we monitor with scans, and a reason not to over-stimulate.
Not entirely. IUI cycles tell us how your ovaries respond to stimulation and confirm that the sperm preparation works, both of which inform an IVF plan. But time is a real cost, particularly over 35, and we will be straight with you about when it is time to change route.
Not sure which one applies to you? That is exactly what the first conversation is for. Start with a free 15-minute consultation with a Fertility Specialist — no referral needed, and no obligation. Book a free consultation, or read about IUI and IVF here first.
Next step: see every price we charge on our prices page.
