What is IUI?
IUI involves placing prepared (washed and concentrated) sperm directly into the uterus around the time of ovulation. By bypassing the cervix, it gives sperm a head start and increases the number reaching the fallopian tubes. IUI can be done in a natural cycle or combined with mild ovarian stimulation to release more than one egg.
How the IUI Cycle Works
Day 1: Period begins; you call the clinic to start a cycle
Days 2-12: Optional fertility medications (letrozole, clomid or low-dose injectables)
Days 10-14: Ultrasound and blood test monitoring of follicle growth
Trigger injection: A precisely timed hCG shot to release mature eggs
IUI procedure: A simple, quick procedure (5-10 minutes) using a thin catheter — similar to a smear test
Two-week wait: Pregnancy test 14 days after insemination
Success Rates
Per cycle: 10-15% under 35, declining with age
Cumulative: around 40-50% over 3-4 cycles for under 35s
Most clinics recommend 3-4 cycles before moving to IVF
Best results with mild stimulation, good sperm quality and patent tubes
Twin rate is around 5-10% with stimulation
Is IUI Right for You?
Suits: mild male factor, unexplained infertility, single women or same-sex couples using donor sperm
Less suitable: blocked tubes, severe male factor, advanced age, low ovarian reserve
Lower cost than IVF (typically £700-£1,500 per cycle in the UK)
Less invasive — no egg retrieval, no embryo transfer
A reasonable first step if you meet the criteria