IUI is low-complexity assisted reproduction: sperm is processed in a lab and placed directly into the uterus at the moment of ovulation, usually combined with ovulation induction. IVF is high-complexity: the ovaries are stimulated, the eggs are collected by aspiration under anesthesia, fertilized in the lab, and the embryos are transferred to the uterus.
| IUI | IVF | |
|---|---|---|
| Complexity | Low (level 2) | High (level 3) |
| What happens | Processed sperm placed in the uterus at ovulation | Eggs collected and fertilized in the lab; embryos transferred to the uterus |
| Usually combined with | Ovulation induction | Ovarian stimulation with daily injections |
| Success rate | 10 to 20% per cycle | 40 to 55% per transfer under 35, falling with age |
| Typical indications | Mild male factor, cervical factor, unexplained infertility, lesbian couples, single women | Tubal factor, some cases of endometriosis, unexplained infertility after insemination, severe male factor (with ICSI) |
| On the ladder | 3 to 6 cycles with induction | 1 to 3 cycles before reassessing |
Rates as given in the book's treatment chapter, which draws on the ESHRE and CDC assisted reproduction reports.
Timed intercourse, the other low-complexity option, combines ovulation induction, monitoring and guidance on having sex at the ideal moment, with a success rate of 10 to 15% per cycle in couples with an isolated ovulatory factor.
| Age | Success per transfer (own embryo) |
|---|---|
| Under 35 | 40 to 55% |
| 35 to 37 | 30 to 40% |
| 38 to 40 | 20 to 30% |
| 41 to 42 | 10 to 15% |
| Over 43 | Less than 5% (donor eggs frequently recommended) |
These are general rates. Ask your clinic for its own numbers for your age and diagnosis.
With donor eggs, success rates are significantly higher, 50 to 60% per transfer, regardless of the recipient's age. ICSI is a variation of IVF in which a single sperm is injected directly into each egg; its classic indication is severe male factor.
On the high-complexity side, gamete donation is indicated in cases such as premature ovarian failure or severely reduced ovarian reserve with advanced age, and PGT, the genetic analysis of the embryos before the transfer, can be indicated in advanced maternal age (35+) or recurrent miscarriage.
On the book's treatment ladder, IUI with induction comes before IVF: usually 3 to 6 cycles of IUI, then IVF for 1 to 3 cycles before the strategy is reassessed. Skipping rungs can be justified in specific cases, such as advanced age or severe diagnoses. For tubal factor, for example, the book says IVF is frequently the most direct path.
IVF also asks more of you: it is a 4 to 6 week process in 5 phases, from ovarian stimulation and egg retrieval to the two-week wait before the blood test. Which option fits your case is a decision to make with your specialist, with your age and your diagnosis on the table.
IUI and IVF are part of Chapter 34 of Map to the Positive, in Station IV (Signs), which lays out every treatment level, gamete donation, PGT and the full ladder. Chapter 35 then demystifies IVF step by step, with the questions to ask before you start, and Chapter 36 covers how to protect your mental health through treatment.
Take 30 days. If it does not give you more clarity than everything you have read for free so far, ask for a refund and you get every cent back. We cannot promise you a pregnancy. We can promise you will not be guessing.
References: ESHRE Annual Report on ART in Europe (2023). · CDC ART National Summary Report (2022). · NICE Clinical Guideline CG156. Fertility problems: assessment and treatment.