No period yet: when a first period is late

The NHS advises a check if your first period has not arrived by 15, or by 13 if there are no other signs of puberty. You can also ask for advice earlier if you are concerned about your growth or development.

If friends are already having periods, it can be hard to separate their experiences from your own questions. At the appointment, ask about the changes you have noticed and any checks you might need. Make time for your own questions about what happens next.

Puberty begins before your first period

Breast development and growth of underarm or pubic hair are signs of puberty. A first period comes later in that process. The NHS says periods typically begin about 2 years after breasts start growing. This describes a common sequence; it cannot tell you when your own periods will begin.

Primary amenorrhoea is the medical term used when a first period has not begun. It differs from secondary amenorrhoea, which refers to periods stopping after they have started. An assessment looks at puberty as well as periods, because causes can involve hormone signals, the ovaries or how the reproductive organs developed.

Why you may see different ages online

NHS period-specific guidance uses 15 without a first period, or 13 without other signs of puberty. Its more recently reviewed missed-period page also advises a GP check if periods have not started by 15.

In the US, ASRM recommends investigation when there has been no first period by 15 despite other pubertal development, or no breast development by 13. MedlinePlus defines delayed puberty as no breast development by 13 or no periods by 16, but also says to contact a clinician if puberty has not begun by 13 or is not progressing.

These sources use different definitions and referral wording. You can still ask about a concern before those ages. Tell the GP or paediatric clinician your age and which changes you have noticed, rather than trying to choose the right label before the appointment.

The possible explanations

Later puberty can run in families. Sometimes development simply begins later, and no treatment is needed. A clinician may ask when close family members started puberty, alongside questions about your own health and growth.

Other explanations include not getting enough nutrition, intensive training, long-term conditions such as coeliac disease or diabetes, and problems involving ovarian or brain hormone signals. Previous cancer treatment and some genetic conditions can also affect puberty. A clinician can assess these possibilities. The timing of a first period alone cannot tell you the cause.

What an appointment may involve

Expect questions about family history, eating, exercise and health, followed by an examination. Tests may include hormone blood tests, a hand or wrist X-ray to assess bone maturity, or an ultrasound or MRI when needed. Your clinician will choose tests to check your development and look for a cause.

You can ask what each part of an examination involves before it begins. If a parent or carer is coming with you, decide what you would like them to help explain. They can bring questions about growth or family history while leaving room for your own questions.

Getting support while the cause is checked

Contact your GP (UK), or doctor or paediatric clinician (US or elsewhere), if you have recurring lower tummy or pelvic pain without a first period; do not wait for the referral ages above. Go to A&E now (UK), or an emergency department (US or elsewhere), if you cannot pass urine or have severe tummy pain.

Treatment depends on what is found. It may involve treating an underlying condition, support with nutrition or hormones to help puberty progress. Emotional distress is also a reason to discuss treatment and support. Your GP or specialist can explain the options; do not try to start periods with hormones or supplements on your own.

Book with a GP in the UK, a doctor or paediatric clinician in the US, or your local primary care service elsewhere, using the advice above. Before leaving, ask when development will be reviewed, whether a specialist referral is planned and who to contact if you have further concerns.