Navigating the Changes of Puberty

Puberty in girls typically begins between ages 8 and 13, triggered by rising levels of estrogen and progesterone. The first visible signs are usually breast development and the growth of pubic and underarm hair. Around the same time, vaginal discharge often changes – one of the earliest signals that a first period is on the way. The body is preparing for menarche, the first menstrual period, which on average occurs between ages 10 and 16.

The first period, medically called menarche, is an important milestone. It signals that the body has begun working in a cyclical pattern. Early periods are often irregular – sometimes heavier, sometimes lighter, sometimes earlier, sometimes later. That's completely normal. The body needs time to find its rhythm. In the first one to two years after menarche, cycle lengths anywhere between 21 and 45 days are entirely typical. Heavy bleeding or cramps in the early years are also common and usually not cause for concern, though they're worth keeping an eye on and discussing with a healthcare provider if they feel unmanageable.

The hormonal shifts of puberty don't just affect the body – they affect the brain too. Estrogen and progesterone actively influence mood, emotional sensitivity and how intensely feelings are experienced. Many girls go through a period of mood swings that feel more intense than anything they've experienced before. This is biologically explainable and not a sign of weakness or oversensitivity. Understanding that hormones directly shape emotions can make a real difference in how girls and their families navigate this time.

Teena was developed specifically for young women during and after puberty. With Teena, girls can start learning to observe, understand and make sense of their cycle from the very beginning. That builds confidence, reduces uncertainty and lays the foundation for a strong sense of body literacy that lasts a lifetime. Cycle awareness isn't just an adult topic. It starts right here, in this phase of life.

Open conversations about body changes, the first period and cycle health don't come naturally to everyone – but they make an enormous difference. Girls who enter puberty well informed experience it as less frightening and more as a normal part of life. In this section you'll also find practical tips for parents: how to open the conversation about periods, what to say, what to avoid and how to be a genuinely supportive presence for your daughter during this time.