IUI or IVF: how to think about the choice
What each involves
IUI — prepared sperm is placed directly into the uterus around ovulation. Usually with mild stimulation or in a natural cycle. Less invasive, less expensive, no egg retrieval.
IVF — eggs are retrieved, fertilised in the laboratory, and an embryo transferred. More involved, more expensive, higher success per cycle.
Where IUI is reasonable
Unexplained infertility of shorter duration. Mild male factor. Ovulatory dysfunction where ovulation induction is working. Where intercourse is difficult. Donor sperm treatment.
IUI requires at least one open fallopian tube and reasonable sperm parameters. Both need establishing before starting rather than after a failed cycle.
Where IVF is the better starting point
Blocked or damaged tubes. Significant male factor. Where PGT-M is needed for a known genetic condition. Advanced maternal age with reduced reserve, where time matters. After several unsuccessful IUI cycles.
The question that actually decides it: how many cycles
Most IUI pregnancies occur in the first three to four cycles. Continuing well beyond that has diminishing returns, and the cumulative cost can approach a single IVF cycle without the higher per-cycle chance.
Agree in advance how many IUI cycles you will do before reconsidering. That decision is much easier made before starting than after the third negative test.
Age changes the calculation
For a woman in her late thirties or older, the time spent on several IUI cycles has a real cost in declining egg quality and quantity. Where reserve is already reduced, moving to IVF sooner is often the better use of time, even though IUI is cheaper per attempt.
Age is a predictor of live birth. AMH and AFC predict how you will respond to stimulation, but ESHRE explicitly does not recommend them for predicting pregnancy or live birth — so a reassuring AMH at 40 is not a reason to spend a year on IUI.
Comparing success rates properly
Ask for figures per cycle started, in your age band, from your own clinic. Per-transfer or per-pregnancy figures are not comparable between the two treatments, and national averages will not reflect your situation.
The honest summary
IUI is a reasonable first step for defined indications, in younger women, with a pre-agreed cycle limit. It is not a milder version of IVF that works for everyone, and drifting through repeated cycles without a plan is the failure mode to avoid.
Frequently Asked Questions
Is IVF more successful than IUI?▾
Yes — significantly. Per-cycle live birth rates for IUI (10–15% under 35) are much lower than IVF (40–50%). However, IUI is much cheaper and less invasive. Doing 3–4 IUI cycles before IVF is an evidence-supported cost-effective pathway for women under 38 with no blocked tubes and adequate sperm counts.
How many IUI cycles before IVF?▾
ASRM 2023 recommends 3–6 IUI cycles with ovarian stimulation before moving to IVF for women under 38 with unexplained infertility, normal tubes, and adequate sperm. For women 38 and over, IVF is typically recommended as first-line because per-cycle IUI rates are too low to justify the time investment.
Can IUI work with low sperm count?▾
IUI requires a minimum total motile sperm count (TMSC) of 5–10 million after sperm preparation. Below 5 million TMSC, IUI success rates are very low and IVF with ICSI is recommended. Between 5 and 20 million, IUI is worth trying for 3 cycles before escalating.