Follitropin alfa
Gonadotropins
Gonadotropins
Recombinant human FSH, injected under the skin. It makes ovarian follicles grow for ovulation induction and IVF.
Also called: Recombinant human FSH (r-hFSH)
Quick facts
- Group
- Gonadotropins
- Target
- Follicle-stimulating hormone receptor (FSHR)
- Used for
- Ovulation induction
- Key effects
- Abdominal discomfort
- Monitor
- Transvaginal ultrasound · Serum oestradiol
- ATC
- G03GA05
No doses: the clinician sets them by the current guideline.
Mechanism of action
The figure shows human FSH bound to the whole extracellular domain of the human FSH receptor. Follitropin alfa is recombinant human FSH and binds the receptor in the same way.
Follitropin alfa is human follicle-stimulating hormone made in mammalian cells by recombinant DNA technology, so it is purer and more consistent than FSH purified from urine. It binds FSH receptors on ovarian granulosa cells, a Gs-coupled receptor that raises cAMP, and makes follicles grow and mature and produce oestradiol. A low, stepwise regimen aims at one dominant follicle (ovulation induction); greater stimulation recruits several follicles for in vitro fertilisation. Ovulation is then triggered separately, usually with hCG.
- Follitropin alfa binds FSH receptors on granulosa cells
- cAMP rises and follicles are recruited and grow
- Mature follicles make oestradiol
- hCG (or another trigger) then releases the oocytes
Indications
- Ovulation induction in anovulatory infertility that did not respond to anti-oestrogen drugs such as clomifene Female infertility →
- Controlled ovarian stimulation for in vitro fertilisation Female infertility →
Adverse effects
Common
- Abdominal discomfort and bloating from enlarged ovaries
- Local reactions at the injection site
Contraindications
- Primary ovarian failure: the ovaries cannot respond, so it is not used
- Hypersensitivity to follitropin alfa
Key interactions
- Chorionic gonadotrophin (hCG)
- Given after follitropin alfa to trigger ovulation; it adds to the risk of ovarian hyperstimulation
- Clomifene
- Often tried before gonadotropins; follitropin alfa is used when anti-oestrogen treatment fails
What is monitored
- Transvaginal ultrasound of follicle number and size
- Serum oestradiol
- Symptoms of ovarian hyperstimulation: abdominal pain, swelling, nausea, breathlessness
Administration and safety
- Subcutaneous injection, usually by the patient after training
- Pens or vials are stored as the product instructs and not shared
- Treatment is supervised in a fertility service that can monitor follicles
Pregnancy and breastfeeding
It is used to achieve pregnancy; it is not given once pregnancy has started.
Nursing care
- Teach self-injection technique and site rotation
- Explain the warning signs of ovarian hyperstimulation and when to seek urgent care
- Explain the chance of multiple pregnancy before treatment
- Keep monitoring appointments: the trigger is timed by ultrasound
Pharmacokinetics
- Absorption
- Given by subcutaneous injection
Test yourself
Think of the answer, then tap the question to see it.
On which cells does follitropin alfa act in the ovary?
Granulosa cells, through the FSH receptor, making follicles grow and produce oestradiol.
Why is ovulation triggered with hCG after follitropin alfa?
FSH grows the follicles but does not cause ovulation; hCG mimics the LH surge and releases the mature oocytes.
Which two risks are explained before ovarian stimulation with follitropin alfa?
Ovarian hyperstimulation syndrome and multiple pregnancy.
Connections
← Back to the class: Gonadotropins
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: The Effect of Follitropin Alfa in Controlled Ovarian Stimulation Protocol for In Vitro Fertilization Cycles (Journal of Reproduction & Infertility (PubMed Central), 2023); Recombinant follicle‐stimulating hormone (follitropin alfa) for ovulation induction in Japanese patients with anti‐estrogen‐ineffective oligo‐ or anovulatory infertility: results of a phase II dose–response study (Reproductive Medicine and Biology (PubMed Central), 2009); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.