What's the difference between IUI and IVF, and how do doctors decide which one?

IUI (intrauterine insemination): prepared sperm is placed into the uterus around ovulation, often with mild medication to stimulate ovulation. It suits cases like mild male factor, ovulation problems or unexplained infertility — provided at least one fallopian tube is open. IVF: eggs are collected, fertilised in the lab and the resulting embryo(s) transferred to the uterus. It's recommended for blocked tubes, severe male factor (often with ICSI), endometriosis, advanced maternal age, or after several unsuccessful IUIs. IVF isn't automatically 'better' — the right choice depends on age, how long you've been trying, tubal status, sperm quality and ovarian reserve. Many doctors try up to three IUIs in suitable couples before moving on. Ask your doctor to explain why they're recommending one over the other for *your* tests.