Girls start periods at different ages. Still, if a first period has not begun by age 15, it is worth arranging a medical assessment. This is not a reason to panic or to compare a girl with her classmates. It is a way to check whether puberty is progressing as expected and whether any support is needed.
What might the visit cover?
A clinician may ask about growth, the timing of other puberty changes, nutrition, exercise, stress, medicines, long-term illness and family patterns. Pregnancy possibility may be discussed where relevant. A respectful consultation should explain why each question is being asked and preserve the adolescent's privacy.
Depending on the history and examination, tests might include blood tests or other investigations. There is no single “period-starting” medicine that fits all causes. Sometimes the issue is a normal variation; sometimes thyroid, hormonal, nutritional or anatomical factors need assessment or specialist care.
How to support a teenager
Avoid promising that a specific test or treatment will start a period. Ask what she wants to know and give her a chance to speak directly to the clinician. Bring prior growth or medical records if available. A trusted adult can help her remember questions without taking over the conversation.
If the girl also has severe abdominal pain or becomes acutely unwell, seek prompt care. Otherwise, book a non-urgent consultation to decide the next step, including referral to gynaecology or endocrinology if indicated.