Gonadotrophin
Pregnancy: Used in ART cycles — not used during pregnancy itself
Follicle Stimulating Hormone (FSH)
Brand names: Gonal-F (follitropin alfa), Menopur (menotrophin), Bemfola, Ovaleap
Adult dose
Dose: Ovulation induction: starting 75–150 units SC OD, adjusted every 7 days based on USS response. IVF: 150–225 units/day (adjusted per protocol). Maximum stimulation: 450 units/day.
Route: Subcutaneous injection
Frequency: Once daily (stimulation phase)
Max: 450 units/day
For infertility due to anovulation, hypogonadotrophic hypogonadism, and ART (IVF/ICSI). Requires ultrasound monitoring for follicle development. Risk of OHSS — titrate carefully.
Paediatric dose
Route: N/A
Frequency: N/A
Max: Not applicable
Not applicable in paediatric patients
Dose adjustments
Renal
No dose adjustment required
Hepatic
No dose adjustment required
Clinical pearls
- OHSS risk: higher in women with PCOS, high AFC, high AMH, or previous OHSS — lower starting doses essential
- Severe OHSS can be life-threatening — ascites, haematocrit rise, thromboembolism, renal failure
- Monitoring: transvaginal USS every 2–3 days to assess follicle number/size; oestradiol levels
- GnRH antagonist cycles: lower OHSS risk vs long GnRH agonist protocols; now preferred in high-risk patients
Contraindications
- Ovarian cysts (not due to PCOS)
- Unexplained uterine bleeding
- Active thromboembolic disease
- Ovarian or uterine cancer
Side effects
- Ovarian hyperstimulation syndrome (OHSS) — mild to severe
- Injection site reactions
- Bloating
- Pelvic pain
- Multiple pregnancy risk
- Ectopic pregnancy risk
Interactions
- Clomifene — combined stimulation protocols possible
- GnRH agonist/antagonist — standard IVF protocols co-administer
Monitoring
- Transvaginal USS (follicle number and size)
- Serum oestradiol
- Signs of OHSS (abdominal distension, weight gain >2 kg/day)
Reference: BNFc; BNF; ESHRE Stimulation Guidelines; NICE CG156 Fertility. Verify against your local formulary and the latest BNF before prescribing.