[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Gonadotropins](https://durgical.com/en/pharmacology/classes/gonadotropins/) › Follitropin alfa

# Follitropin alfa

## Gonadotropins?

Gonadotropins

Recombinant human FSH, injected under the skin. It makes ovarian follicles grow for ovulation induction and IVF.

Updated Nov 1, 2026

Also called: Recombinant human FSH (r-hFSH)

## Quick facts

**Group**
[Gonadotropins](https://durgical.com/en/pharmacology/classes/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.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

◎**Follicle-stimulating hormone receptor (FSHR)**Follitropin alfa

ⓘ 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.

**Target in 3D:** Follicle-stimulating hormone receptor (FSHR). PDB structure 4AY9 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/4AY9) · Drag to rotate · pinch to zoom

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 →](https://durgical.com/en/conditions/female-infertility/)
- Controlled ovarian stimulation for in vitro fertilisation [Female infertility →](https://durgical.com/en/conditions/female-infertility/)

## Adverse effects

### Common

- Abdominal discomfort and bloating from enlarged ovaries
- Local reactions at the injection site

### Serious (rare, important)

- Ovarian hyperstimulation syndrome, more frequent with higher exposure
- Multiple pregnancy (twins or more)

## 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

## Memory aid

FOLLItropin makes FOLLIcles grow; hCG then pulls the trigger.

## 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.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/follitropin-alfa/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## Connections

## Related drugs 3

- [Chorionic gonadotrophin](https://durgical.com/en/pharmacology/chorionic-gonadotrophin/)
- [Clomifene](https://durgical.com/en/pharmacology/clomifene/)
- [Letrozole](https://durgical.com/en/pharmacology/letrozole/)

## Related conditions 1

- [Female infertility](https://durgical.com/en/conditions/female-infertility/)

[← Back to the class: Gonadotropins](https://durgical.com/en/pharmacology/classes/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](https://pmc.ncbi.nlm.nih.gov/articles/PMC10402457/) (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](https://pmc.ncbi.nlm.nih.gov/articles/PMC5891811/) (Reproductive Medicine and Biology (PubMed Central), 2009); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=G03GA05) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/follitropin-alfa/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/follitropin-alfa/