Precocious puberty in girls

Information for parents/carers

Introduction

This leaflet explains what happens to girls during puberty, and how to understand early puberty. It should help you make sense of some of the medical words you may hear, and give you an idea of what to expect from your clinic visit.

Puberty in Girls

On average, girls start the physical changes of puberty at around the age of 10-11 years old. However, there is a wide age range and puberty can start as early as 8 years old. Puberty usually progresses over 2 to 3 years and involves a series of reactions in the brain and body, controlled by hormones. Hormones are the body’s chemical messengers.

Puberty starts when a part of the brain called the hypothalamus releases a hormone called Gonadotrophin Releasing Hormone (GnRH). This hormone stimulates the pituitary gland in the brain to release two more hormones called Lutenising Hormone (LH) and Follicle Stimulating Hormone (FSH), which tell the ovaries to make the hormones Progesterone and Oestrogen. These are the hormones that control puberty, the menstrual cycle (periods) and the release of eggs from the ovaries (ovulation).

The increased production of oestrogen during puberty leads to a series of changes in the body. The speed and sequence of these changes are the same for most girls. The first clear sign that puberty has started are the breasts which begin to bud (or enlarge). Then, pubic hair (thick hair strands in the nether regions) and under-arm (axillary) hair will start to grow, and a faint body odour may be noticeable. Skin spots or acne may also develop. It is usually at this stage that girls will begin their growth spurt.

Inside the body, the uterus (womb), ovaries and fallopian tubes grow in size, and when they reach maturity, the menstrual cycle (or periods) begin. There may be an increase in the amount of fat tissue around the breasts and hips. The time when menstrual periods start is called ‘menarche’ (pronounced ‘menarky’) and this usually occurs 2 to 3 years after the start of breast changes. Usually, the growth spurt will have slowed by the time menarche occurs.

Precocious puberty

Precocious puberty occurs ten times more commonly in girls than boys. Puberty is classed as precocious if it starts in girls before the age of 8 years old.

However, over several years, the age at starting puberty has been gradually getting earlier and earlier. It is now estimated that 5 to 10% of girls start puberty between ages 7 to 8 years old. This is more likely in some ethnic groups (e.g. African or South Asian origin) or if another family member also had early puberty (this is due to shared genetic factors).

Why is precocious puberty important?

In most cases there is no underlying cause to explain precocious puberty, and this is due to the brain sending pubertal signals earlier that it should. Rarely, precocious puberty may be a sign of some other medical conditions. This is particularly the case if puberty starts very early (e.g. before age 6 years) or in girls with some other medical conditions or illness.

Even if there is no other unusual medical cause, early puberty may have some disadvantages. Firstly, adult height may be short in some girls who are already short at the start of puberty, or if puberty starts very early (e.g. before age 6 years). This is because bones will mature at a faster rate than is usual. Towards the end of puberty, the bones fuse, which means they cannot grow any more. If they fuse too early, as can happen in precocious puberty, a girl may not reach her full height potential.

Secondly, some girls are concerned that they look unusually well-developed compared to other girls of the same age. In many cases, this can be managed by simple reassurance. Your child may be wondering what is happening to her body and asking why she is different from her friends. You can explain and emphasise that what is happening to her body is a normal process for older girls. She may benefit from sensitive support by their school or communities (e.g. to be allowed not to change in front of other girls; to use a sports bra or top). As parents you may be feeling anxious about how you are going to deal with helping her cope with the physical and psychological changes she is undergoing. The most important thing to remember is that you are not alone; many other families and girls are going through this too.

Encourage your child to talk through her worries with you. Use the proper words for body parts if you can, although the most important thing is that you talk openly and honestly about what is happening and how she feels.

Very young children may not have the vocabulary or understanding to be able to communicate in this way about what is happening. Give your child time to communicate with you, perhaps using stories and play. Please let us know if you need help or support with any aspect of this. Our Endocrine nurses and clinical psychologist can offer support and there is also a list of help groups at the end of this leaflet.

Clinic Visit and investigations

At your clinic visit, you will have met the paediatric Endocrine Nurses who weighed and measured your child. They will also ask to measure the height of parents who attend clinic, as this helps us to predict the growth of your child.

You will have seen one of our Endocrine Doctors who will ask you what is worrying you/your child and usually ask to examine your child in order to see how far through puberty they are. All this information, along with the following investigations, is useful when making a diagnosis.

Physical Examination

The doctor may have asked to examine your child, including their breasts, axillary and pubic hair. It is hospital policy that another member of staff is present for this. This person is called a ‘chaperone’ and will be asked to observe the examination.

We are aware that physical examination can make children and families feel uncomfortable. However, this gives us important information about your child. Please tell us if you or your child felt uncomfortable with the examination. We can talk with you about future examinations, what it will involve, why and whether it is necessary. You have the right to say no to this, although it may be difficult for the doctor to make a definite diagnosis and manage your child’s condition without examination.

As we are a teaching hospital, we may ask your permission for a medical student or other qualified observers to join the consultation. If you agree to this, you can still ask that they are not present when your child is examined.

X-Ray

An x-ray of the left hand and wrist helps to find out the ‘bone age’ of your child, which means how mature the bones are. If puberty has progressed, the bone age may be older than your child’s actual (chronological) age.

Scans

The doctor may request a head scan (M.R.I.) to look at the endocrine glands in the brain. Sometimes they request a pelvic ultrasound scan (lower abdomen) to assess the development of the uterus (womb) and ovaries. If these scans are needed, they will usually take place on a different day to your clinic appointment.

Blood Tests

Blood tests to look at levels of hormones (e.g. LH, FSH and Oestrogen) can be very useful to establish whether puberty is really underway, and if so why. This often takes the form of an “LHRH” test. This test involves inserting an intra-venous cannula (small plastic tube), taking some baseline blood tests, giving a small amount of a synthetic form of GnRH and then measuring the hormone response over an hour.

Diagnosis

Once the various test results are back, if puberty is not yet established, no treatment is indicated. If puberty is underway, we will then discuss with you the pro’s and con’s of starting treatment to stop puberty from progressing.

Pros of treatment

Treatment is usually effective in preventing further progression of puberty and early menarche (periods). Treating can also help to preserve final adult height. The younger your child, the more likely they are to benefit from treatment in terms of height potential. Treatment will also mean that your child does not develop psychologically and emotionally faster than her peers.

Cons of treatment

Treatment does involve giving an intramuscular injection and this can be painful for her. There are no serious reported side effects happening during treatment and there are no known long term negative effects of treatment (see below for more details).

Treatment to delay the progression of puberty

The treatment to stop puberty which is licensed for use in children is an Intra-Muscular (IM) injection called Decapeptyl SR. This medication blocks the GnRH signal to the pituitary gland which usually starts the series of hormonal changes.

Treatment with Decapeptyl SR injections is started by the Paediatric Endocrine Nurses at the Weston Centre. There are both 3 and 6 monthly versions of the injection available and your Consultant will discuss with you which they think is most suitable for your child. Prior to the second injection, a blood sample may be taken to check that the puberty hormone levels have been suppressed.

Your child may feel nervous before her first injection; this is usually because she doesn’t know what to expect, and it may be helpful to prepare her beforehand. You could explain that the injection may hurt a bit but reassure her that it will be over quickly and that you will be with her so she can cuddle up to you if she wants.

Other girls tell us that using an ice pack, cold spray, a “buzzy bee” and sometimes applying local anaesthetic cream to the injection site (the upper outer quarter of the buttock) helps, and the injection isn’t as bad as they thought it would be.

During treatment, some girls will notice a partial or even complete reduction of their breast development – for other girls (particularly if puberty has been long-standing) breast size remains the same but doesn’t continue to grow larger. Any pubic or underarm hair usually remains (or even slightly increases with time).

Are there any side effects?

There are no known serious short or long term side effects from the treatment. Sometimes there can be mild reddening, itching or bruising around the injection site and some girls experience transient headaches when they start. Due to the falling levels of oestrogens, some girls may experience some initial bleeding or spotting. There is no evidence that the treatment will affect your child’s fertility in the future.

How long will the treatment continue for?

Treatment will be continued until it is time to let puberty continue naturally. This is usually when girls reach 10 or 11 years old, but the decision will be agreed between you and the Endocrine Doctor. After treatment is stopped, puberty should resume at a normal rate.

Contacting the Paediatric Endocrine Nurses

The Paediatric Endocrine Nurse Specialist team can be contacted on (01223) 217496 if you need any further help, advice or support.

Useful websites

• The Child Growth Foundation (opens in a new tab)
• British Society of Paediatric Endocrinology and Diabetes (B.S.P.E.D.) (opens in a new tab)