- IUI is the most common first-line fertility treatment: less invasive, less expensive, and less medically intensive than IVF.
- Success rates are modest (10–20% per cycle under 35) but the low cost allows multiple attempts. Most REs recommend 3–4 cycles.
- IUI works best for: mild male factor, unexplained infertility, cervical issues, single women or same-sex couples using donor sperm.
- IUI is NOT effective for: blocked tubes, severe male factor, advanced age (40+), or severe endometriosis.
- The procedure takes 15 minutes, feels like a Pap smear, needs no anesthesia. You walk out and resume your day.
What Is IUI?
Intrauterine insemination (IUI) places washed, concentrated sperm directly into the uterus using a thin catheter, timed to coincide with ovulation. The goal: increase the number of sperm that reach the fallopian tubes so one can fertilize an egg.
Think of it as giving sperm a significant shortcut. In natural conception, sperm must navigate through the cervix, uterus, and up to the fallopian tubes—a journey that filters out the vast majority. IUI deposits millions of concentrated, motile sperm directly past the cervix.
Unlike IVF, fertilization happens naturally inside your body. No egg retrieval, no lab fertilization, no embryo transfer. Simpler, cheaper, less physically demanding—but also less controllable, which is why success rates are lower.
Who Is IUI Best For?
Strong Candidates
- Mild male factor infertility: Slightly below-normal count, motility, or morphology. Sperm washing compensates for mild issues.
- Unexplained infertility: All tests normal but not conceiving. IUI + meds increases eggs and ensures precise timing.
- Cervical factor: Hostile cervical mucus, scarring, or other issues impeding sperm transport.
- Ovulation disorders: Combined with ovulation-inducing medications (Clomid, letrozole, gonadotropins).
- Donor sperm: Single women, same-sex female couples, or couples using donor sperm.
- Sexual dysfunction: Conditions making intercourse difficult or impossible.
IUI Is NOT Effective For
- Blocked fallopian tubes: Sperm and egg can’t meet. IVF bypasses tubes entirely.
- Severe male factor: Total motile count under 5M after washing is too low. ICSI with IVF is indicated.
- Advanced age (40+): Egg quality is the issue; IUI doesn’t address that. IVF with PGT gives better odds.
- Severe endometriosis: Anatomical distortion reduces IUI effectiveness.
- Multiple failed IUI cycles: After 3–4 failures, additional cycles have significantly diminished returns.
IUI Success Rates
| Scenario | Per-Cycle Rate | After 3–4 Cycles |
|---|---|---|
| Natural cycle IUI (no meds), under 35 | 5–10% | 15–30% |
| IUI + Clomid/Letrozole, under 35 | 10–15% | 30–45% |
| IUI + gonadotropins, under 35 | 15–20% | 40–50% |
| IUI + meds, age 35–37 | 10–15% | 25–40% |
| IUI + meds, age 38–40 | 5–10% | 15–25% |
| IUI + meds, age 40+ | 2–5% | 8–15% |
| IUI with donor sperm, under 35 | 15–25% | 45–60% |
Natural cycle IUI relies on your single monthly egg. Medicated IUI develops 2–3 follicles, giving 2–3 targets instead of one—roughly doubling per-cycle success. Trade-off: 10–20% twins risk with oral meds, up to 30% with injectables.
IUI vs. IVF Comparison
| IUI | IVF | |
|---|---|---|
| Cost per cycle | $500–$4,000 | $20,000–$25,000 |
| Success (<35) | 10–20% | 50–55% |
| Invasiveness | Minimal | Moderate (retrieval) |
| Medications | Oral or low-dose | High-dose daily injectables |
| Appointments | 2–4 per cycle | 8–14 per cycle |
| Time off work | Minimal to none | 1–2 days |
| Best for | Mild issues, young patients | Blocked tubes, severe male, 38+ |
Blocked tubes, very low sperm count (<5M total motile), age 40+ with low reserve, severe endometriosis (Stage III/IV), or after 3–4 failed IUI cycles. Every month on ineffective treatment is another month of age-related decline.
The IUI Process
Day 1–3: Cycle begins (period starts). If using meds, start Clomid/letrozole on Day 3–5 for 5 days, or begin gonadotropin injections.
Day 10–14: Monitoring appointment. Ultrasound for follicle size, blood work for hormones. When follicles reach 18–22mm, insemination is timed.
Trigger shot: hCG injection triggers ovulation ~36 hours later. IUI scheduled accordingly.
IUI day: Sperm sample provided that morning, lab washes and concentrates it. The procedure takes ~15 minutes: thin catheter through cervix, sperm deposited into uterus. Brief cramping possible; most patients feel little to nothing. Rest 10 minutes, go about your day.
Two-week wait: Progesterone support may be prescribed. Pregnancy blood test ~14 days after IUI.
IUI Cost Breakdown
| Component | No Meds | Clomid/Letrozole | Gonadotropins |
|---|---|---|---|
| Monitoring | $200–$500 | $300–$800 | $500–$1,500 |
| Sperm wash + IUI | $300–$1,000 | $300–$1,000 | $300–$1,000 |
| Medications | $0 | $30–$100 | $500–$2,000 |
| Trigger shot | $0 | $100–$250 | $100–$250 |
| Total | $500–$1,500 | $800–$2,200 | $1,500–$4,000 |
Insurance coverage for IUI is more common than IVF. Many mandate states cover IUI, and even plans without fertility benefits may cover monitoring under general gynecological care. Always verify with your insurer.
The Cost Math: 3–4 IUI vs. 1 IVF
Three medicated IUI cycles at $1,500–$2,500 each = $4,500–$7,500 total with ~30–45% cumulative success under 35. One IVF cycle at $20K–$25K has 50–55% single-cycle success. For young patients with no severe factors, trying 3 IUI cycles first is smart: spend less, less intensive treatment, meaningful odds. If it doesn’t work, move to IVF having invested a fraction. For patients over 38 or with known limiting factors, go straight to IVF.
Frequently Asked Questions
Medical Disclaimer
For informational purposes only. Consult your RE for personalized treatment recommendations.
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Sources
ASRM Practice Committee. SART National Summary. Cohlen et al., Cochrane Database. Bensdorp et al., Lancet, 2015.