Thelarche is the medical name for one of the early stages of puberty in girls. It is often the first visible sign that a girl is starting to go through the physical changes of puberty. The name thelarche comes from the Greek words for nipple and beginning and this stage of puberty is the start of breast development.
Thelarche is caused by levels of the hormone estradial starting to rise and this increase in hormones results in breasts beginning to develop. The development takes the form of small hard lumps which form under the nipple. The lumps may form under one nipple at a time or sometimes under both nipples at once. The small lumps which form are sometimes referred to as breast buds.
The onset of thelarche will normally occur around the age of nine or ten. It is possible for thelarche to begin at an earlier age and in rare case this may be a sign that the girl is suffering from precocious puberty if other signs of puberty are also apparent. It is important to seek medical advice in these cases. If thelarche does occur at an earlier age but the girl exhibits no other signs of puberty then this is referred to as isolated premature thelarche and no medical treatment will need to be given. Thelarche may sometimes occur at an age later than nine or ten and this should not generally be a cause for concern.
A girl may be unprepared for the onset of thelarche because it is one of the first stages of puberty and they may need some reassurance that this is a completely normal part of their physical development. The growing breasts may also feel uncomfortable during thelarche and sore to lie on in bed so it is important to explain that this is normal and to administer a mild painkiller if required.