Puberty: what changes and when

Tender little lumps beneath the nipples can be breast buds: an early part of breast development. They grow gradually over several years. Your first period does not have to arrive alongside the first breast changes.

Changes before the first period

Puberty involves growing taller and changes in body shape. Your hips may widen, and you may notice more body fat around your bottom, hips and thighs. Hair can grow under your arms and around your vulva, becoming thicker over time.

You may sweat more or notice a stronger body smell. Skin can become oilier, with spots or acne. You can ask about these changes when you talk about puberty, as well as asking about periods.

Breast buds can be tender. Breasts may grow quite quickly or remain small, and development happens over time. Someone else’s appearance cannot give you a timetable for your own development.

Hormones send the signals behind these changes. FSH, made by the pituitary gland, helps tell the ovaries to produce oestrogen during puberty. Oestrogen is involved in breast growth and the start of periods. The changes are connected, even when you notice them at different times. If you are worried about the timing, you can ask about the changes you have noticed.

Discharge can arrive first

Clear or whitish fluid in your underwear can appear before your first period. Vaginal discharge is fluid or mucus that helps keep the vagina moist and clean. It is separate from menstrual bleeding.

Discharge that changes in smell, colour or texture, or comes with itching or soreness, needs advice. In the UK, contact NHS 111; in the US and elsewhere, contact your doctor. Describe what changed rather than trying to identify an infection from its appearance.

When changes can start

Published guidance uses different ranges. The NHS describes puberty across children as starting between the ages of 8 and 14 years old. ACOG’s guidance specifically for girls describes changes starting as early as age 8 or as late as 13. These pages describe different groups; neither gives you an exact date for a first period.

ACOG says menstruation usually begins about 2 to 3 years after breasts start developing. The timing is a guide, so it cannot tell you exactly when your first period will arrive. For a parent or carer, it is a useful reason to talk about periods before bleeding starts.

Hormonal changes can also bring stronger emotions and a wish for more privacy. You can ask a trusted adult for help while still asking them to give you space. If you are supporting a young person, ask what they want to know and use the words they understand.

It can help to prepare for the conversation. You could write down the changes you have noticed and roughly when they began, then add the question that is worrying you most. A parent can help with practical details without speaking for you throughout. Ask for explanations in plain language, and say if you would prefer to discuss something privately.

When to book an appointment

Book a GP appointment (UK), or see your doctor or paediatrician (US and elsewhere), if puberty starts before age 8, breast development has not started by age 13, or you are concerned about its timing. The breast-development advice applies even if pubic or underarm hair has appeared.

Book a GP appointment (UK), or see your doctor or paediatrician (US and elsewhere), if your first period has not arrived by age 15, or if 3 years have passed since breast development began without a first period. The NHS gives the age 15 referral point; ACOG also advises review after 3 years without a first period following breast development.

A clinician may suggest blood tests to check hormones and, when needed, imaging. Timing sometimes runs in families, but nutrition, long-term conditions and problems affecting hormones can also play a part. Ask what any proposed test is looking for and when you will discuss the result.