Synopsis
Match ovulation induction, intrauterine insemination, IVF and ICSI to the diagnosed fertility problem, explain a full treatment cycle, reduce multiple pregnancy and avoid ineffective add-ons.
- Ovulation induction treats a defined ovulatory disorder; it is not recommended as stand-alone treatment for unexplained infertility.
- Letrozole is the preferred first-line pharmacological ovulation induction for anovulatory infertility in PCOS in the 2023 international guideline, but its UK fertility use is off-label and requires informed specialist prescribing.
- Gonadotrophin induction requires ultrasound monitoring of follicle number and size to reduce multiple pregnancy and OHSS.
- IUI places prepared sperm in the uterine cavity around ovulation; it does not bypass bilateral tubal occlusion and relies on a suitable total motile sperm population.
- After 2 total years of unexplained infertility, NG257 says discuss either up to 4 cycles of gonadotrophin-stimulated IUI before IVF, or IVF directly, according to benefits, risks and preference.
- IVF uses ovarian stimulation, oocyte retrieval, laboratory fertilisation, embryo culture and transfer; a full cycle includes one stimulation and transfer of all resulting fresh and frozen embryos.
- ICSI is offered with surgically retrieved sperm or frozen-thawed oocytes and considered for sufficiently abnormal semen or previous failed or very low fertilisation, not routinely when semen is normal.
- Use single embryo transfer wherever recommended, never transfer more than two embryos, and avoid endometrial scratch, routine pre-IVF hysteroscopy, receptivity tests, PGT-A to improve live birth and immunological add-ons.
Key red flags
Rapid abdominal distension, severe pain, persistent vomiting, dyspnoea, reduced urine output, syncope or leg or chest symptoms after stimulation requires urgent OHSS and thrombosis assessment.
Sudden focal pelvic pain with nausea after ovarian stimulation may represent adnexal torsion and needs urgent gynaecological assessment.
Heavy bleeding, shoulder-tip pain, collapse or peritoneal signs after oocyte retrieval requires urgent review for intra-abdominal bleeding or other procedural complication.
Fever, escalating pelvic pain or offensive discharge after insemination, retrieval or transfer suggests infection.
A positive pregnancy test with pain or bleeding after assisted conception still requires ectopic and heterotopic pregnancy assessment.
Investigation priorities
Confirm ovulatory, tubal, uterine and semen factors before selecting treatment.
Management branches
A treatable anovulatory disorder is confirmed.
- Correct reversible central or endocrine causes and exclude pregnancy, important tubal disease and major semen factors before induction.
- Use diagnosis-specific treatment such as off-label letrozole for anovulatory PCOS, cabergoline for hyperprolactinaemia or gonadotrophin/GnRH therapy for hypogonadotrophic hypogonadism.
- Monitor gonadotrophin cycles with ultrasound, apply cancellation rules and counsel about multiple pregnancy, OHSS and timed intercourse or insemination.