Labial fusion, or labial adhesion, is when the small inner lips around the entrance to the vagina become sealed together.
In some cases, this can completely seal the vaginal opening, leaving a very small gap at the front that urine passes through.
It's a fairly common condition in girls under seven years old and is usually nothing to worry about.
Causes of labial fusion
It's not certain what causes labial fusion, but it usually occurs as a result of some irritation or inflammation of the vaginal area, known as vaginitis.
This can cause the inner lips of the vulva to become sticky. Without enough oestrogen in the body, which is quite normal before puberty, the lips can stay stuck together and gradually become firmly joined.
The problem is rarely seen in girls after they begin puberty, because this is when they start to produce the hormone oestrogen.
Seeing your GP
For most babies or girls, labial fusion doesn't cause any problems and is often discovered accidentally by a parent or carer during nappy changing or bathing.
Your GP can confirm labial fusion after doing a routine examination of the child's genital area.
Treating labial fusion
A labial fusion or adhesion usually separates naturally without treatment.
Treatment for labial fusion isn't recommended unless there are other symptoms, such as dribbling after urination, which may cause problems or discomfort.
Treatment is with oestrogen cream or ointment applied daily or, very rarely, surgical separation.
A small blob of the cream or ointment is applied daily on to the central line of fusion of the inner lips of the vulva.
This should be continued for four to six weeks until the membrane starts to dissolve and the labia eventually separate completely. When the membrane dissolves, you should stop applying the cream.
To enable the labial edges to heal properly and prevent another labial fusion forming, you should continue to apply an emollient, such as nappy rash cream, for a few months after the fusion has separated.
Oestrogen creams and ointments can occasionally cause side effects, especially if used for periods longer than a few weeks. They shouldn't be used for longer than six weeks. Side effects can include:
- irritation around the genital area
- temporary pigmentation (darkening) of the skin in the genital area
- vaginal spotting or bleeding after you stop using the cream or ointment
Side effects should go away after you stop using the oestrogen cream or ointment.
Surgery is very rarely needed to treat labial fusion. It may be considered if:
- an oestrogen cream or ointment doesn't work
- a fusion is particularly thick and severe
- there's trapped urine in the vagina, which can dribble out after urination and cause vulval soreness
Labial fusions are relatively easy to separate – they can usually be gently pulled apart by hand, or a small blunt probe can be used.
A surgical separation is usually performed under a general anaesthetic, where you're asleep, or local anaesthetic, where the area is numbed, as the procedure can be quite painful and can cause distress.
To allow the labial edges to heal properly and prevent another labial fusion forming, you'll be advised to apply an emollient, such as nappy rash cream or Vaseline, to the labia for a few weeks afterwards.
There's a high chance the fusion will return after treatment, whether you are treated with oestrogen cream or surgery.
Complications of labial fusion
Labial fusion isn't linked to any medical condition and has no long-term implications for your child – it won't affect her future fertility or sexual life.
In most cases, a fusion corrects itself during puberty. In up to 14% of cases, a fusion may recur, but this tendency usually stops before puberty begins.
Rarely, labial fusion can cause:
- infection (such as a urinary tract infection)
- soreness or pain in the genital area
- urine becoming trapped in the vagina, leading to leaking of urine between visits to the toilet