Health condition
Congenital hypogonadotropic hypogonadism
Congenital hypogonadotropic hypogonadism (CHH) is lifelong deficiency of the brain's reproductive hormone signal - absent or partial puberty with low LH and FSH - with normal smell distinguishing it from Kallmann syndrome, and fertility usually recoverable with treatment.
Why trust this guide
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Editorial team
Written by our editorial team from the UK sources listed on each page.
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Sourced from guidance
Checked against current NHS and UK specialist society guidance at the time of review.
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Current for 2026
Reviewed on 2026-09-27 with the next review scheduled for 2027-09-27.
Key facts
The essentials at a glance.
The symptoms to recognise, when to seek help, which specialist to see, and what treatment usually involves.
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The pattern: absent, delayed or stalled puberty with low sex steroids and low or inappropriately normal LH and FSH, once other pituitary disease is excluded
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Distinguishing constitutional delay ('late bloomer') from CHH is the classic dilemma in late adolescence
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Red flags for CHH over simple delay: micropenis or undescended testes at birth, absent smell, family history, or no progress by 18
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Around 10-20% of cases can spontaneously reverse after treatment - periodic supervised withdrawal is worthwhile
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Fertility induction with gonadotrophins succeeds in most; bone density and psychological support belong in the care plan
Understanding the condition
What it is and what happens next.
What causes it, how it is diagnosed, and the treatment routes available in the UK.
What it is and how it feels
Puberty begins when hypothalamic GnRH pulses wake the pituitary; in CHH those pulses never properly arrive. The result ranges from complete absence of development to partial, stalled puberty - and in adults, low libido, infertility, reduced muscle and bone, and the quieter injuries of having developed differently from peers. Because constitutional delay is common and CHH rare, many patients are reassured repeatedly through their teens; the diagnosis is often only made in the twenties.
Diagnosis and treatment routes
Workup excludes pituitary tumours and systemic illness, characterises the hormone pattern, tests smell, and increasingly includes genetic panels spanning dozens of genes. Management is staged: sex steroid replacement to complete development and protect bone; gonadotrophin therapy when fertility is wanted, with good success particularly if testes descended normally; and trial withdrawal every few years given the reversal minority. If puberty never fully arrived for you, it is never too late to be assessed - privately, typically within about two weeks.
Seeing a specialist
Who to see, and how quickly you can be seen.
The specialist for this condition is usually a consultant endocrinologist. Your GP can refer you on the NHS, or you can arrange a private consultation directly.
A quiet reminder
This guide is for information, not medical advice.
Your GP knows your history and can tell you which parts apply to you. If in doubt, see them - and seek urgent care for any of the emergency symptoms described above.
Frequently asked
Common questions about Congenital hypogonadotropic hypogonadism.
Quick, plain-English answers to what people ask us most.
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What is congenital hypogonadotropic hypogonadism?
Congenital hypogonadotropic hypogonadism (CHH) is a condition present from birth in which the brain (specifically the hypothalamus and pituitary gland) fails to produce adequate signals needed to stimulate normal puberty and reproductive hormone production, despite the reproductive organs themselves typically being structurally normal. This leads to absent or incomplete puberty and, without treatment, infertility. It can occur in isolation or alongside other features, such as a reduced or absent sense of smell (in a specific subtype called Kallmann syndrome).
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What causes CHH?
It results from inherited or, sometimes, spontaneously occurring genetic mutations affecting the development or function of specific hormone-producing or hormone-signalling cells in the brain responsible for triggering normal puberty. Numerous different genes have been identified as potential causes, with various inheritance patterns depending on the specific gene involved. Genetic testing can sometimes identify the specific cause, though this isn't found in every case despite thorough testing.
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What symptoms does CHH cause?
The main feature is absent, delayed, or incomplete puberty, which can be identified in both males and females when expected pubertal changes don't occur at the typical age. In the specific subtype Kallmann syndrome, an absent or significantly reduced sense of smell is also present, reflecting a shared developmental link between the relevant brain pathways. Without treatment, infertility due to inadequate reproductive hormone production is also a key feature.
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How is CHH treated?
Treatment typically involves hormone replacement therapy to induce and maintain puberty and secondary sexual characteristics, and, for those wanting to conceive, specific fertility treatments using different hormone regimens designed to stimulate the reproductive system more directly. Treatment approaches differ somewhat between males and females and are tailored to individual goals, including whether fertility is currently desired. A specialist endocrinology team, often with specific reproductive endocrinology experience, guides this individualised treatment.
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Can people with CHH have children?
Yes, with appropriate specific fertility treatment (different from standard puberty-inducing hormone treatment), many people with CHH can achieve pregnancy or conceive a pregnancy with a partner, since the reproductive organs themselves are typically structurally normal; the issue is specifically with the hormonal signal that would normally stimulate them. This distinction is an important and often reassuring point for people with this condition considering future fertility. Discussing fertility goals with a specialist reproductive endocrinologist can help plan the most appropriate approach when the time comes.
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When should I see a specialist?
See a doctor if puberty hasn't started or progressed as expected by the typical age, particularly with an absent sense of smell, for specialist endocrinology assessment. NHS endocrinology referral can take several weeks; a private consultation is typically available within about 2 weeks for earlier specialist assessment.