Chorionic gonadotrophin
Gonadotropins
Gonadotropins
The pregnancy hormone hCG, given by injection. It acts like LH: it triggers ovulation and stimulates testosterone production.
Also called: Human chorionic gonadotropin (hCG), Chorionic gonadotropin
Quick facts
- Group
- Gonadotropins
- Target
- Luteinising hormone/choriogonadotropin receptor (LHCGR)
- Used for
- Selected cases · Induction of ovulation
- Key effects
- Headache · Fluid retention
- Monitor
- Follicle ultrasound · Testicular position and signs
- ATC
- G03GA01
No doses: the clinician sets them by the current guideline.
Mechanism of action
The figure shows human chorionic gonadotropin bound to the full-length human LH/choriogonadotropin receptor with its Gs protein (cryo-EM).
hCG is a placental glycoprotein made of an alpha subunit shared with LH, FSH and TSH and a specific beta subunit. It binds the LH/choriogonadotropin receptor, a Gs-coupled receptor, and raises cAMP. In the testis it stimulates Leydig cells to make testosterone, which can help an undescended testis descend. In the ovary, given after follicles have matured, it mimics the LH surge and triggers final oocyte maturation and ovulation, then supports the corpus luteum.
- hCG binds the LH/choriogonadotropin receptor
- Gs raises cAMP in Leydig, theca and luteal cells
- Testosterone rises in males; in females the LH surge is mimicked
- Mature follicles ovulate and the corpus luteum is supported
Indications
- Prepubertal cryptorchidism not due to an anatomical obstruction Cryptorchidism (undescended testis) →
- Selected cases of hypogonadotropic hypogonadism in males Male hypogonadism →
- Induction of ovulation in anovulatory infertile women after follicle stimulation with menotropins Female infertility →
Adverse effects
Common
- Headache, irritability, restlessness, tiredness or low mood
- Fluid retention (oedema)
- Breast enlargement in males (gynaecomastia)
- Pain at the injection site
Contraindications
- Precocious puberty
- Prostatic carcinoma or other androgen-dependent tumour
- Previous allergic reaction to hCG
Key interactions
- Menotropins and other FSH preparations
- Used in sequence for ovulation induction; together they raise the risk of ovarian hyperstimulation and multiple pregnancy
- Gonadotropin laboratory tests (immunoassays for LH)
- hCG can interfere with the results
What is monitored
- Follicle ultrasound and oestradiol before the ovulation trigger
- Signs of ovarian hyperstimulation: abdominal pain, swelling, rapid weight gain, breathlessness
- Testicular position and signs of early puberty in boys
- Testosterone in men treated for hypogonadism
Administration and safety
- Intramuscular only for this product
- Ovulation induction is supervised by a clinician experienced in infertility treatment
- Prescription hCG injections are not the same as products sold for weight loss, which have no proven benefit
Pregnancy and breastfeeding
It is used to achieve pregnancy, not during it; the label warns it may harm the fetus if given in pregnancy. Gonadotropin treatment often results in twins or other multiple pregnancies.
Nursing care
- Teach the signs of ovarian hyperstimulation and when to seek care urgently
- Record weight and abdominal girth if hyperstimulation is suspected
- In boys, watch for signs of early puberty and stop treatment if they appear
- Use caution and watch for fluid retention in asthma, epilepsy, migraine, heart or kidney disease
- Explain that it does not help weight loss
Pharmacokinetics
- Absorption
- Given by intramuscular injection (this generic product is intramuscular only)
- Half-life
- Longer than that of LH, which is why it can replace the LH surge
Test yourself
Think of the answer, then tap the question to see it.
Why can hCG replace the LH surge in ovulation induction?
It binds the same LH/choriogonadotropin receptor and lasts longer than LH, so one injection triggers final oocyte maturation and ovulation.
How does hCG help an undescended testis in a prepubertal boy?
It stimulates Leydig cells to make testosterone, which can promote testicular descent when no anatomical obstruction is present.
Which two contraindications to hCG relate to hormone-sensitive conditions?
Precocious puberty and prostatic carcinoma or another androgen-dependent tumour (also previous allergy to hCG).
Does hCG help weight loss?
No. There is no evidence that it adds weight loss beyond calorie restriction or reduces hunger.
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: DailyMed - CHORIONIC GONADOTROPIN kit (DailyMed (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.