Labial fusion, or labial adhesion, is when the small lips around the entrance to the vagina become sealed together and covered with a fleshy membrane. It is sometimes seen in babies and young girls and is usually nothing to worry about.
The membrane usually completely seals the vaginal opening, leaving a very small gap at the front through which urine passes.
For most babies or girls, labial fusion does not cause any problems and is often discovered accidentally by a parent or carer during nappy changing or bathing.
Who is affected?
Labial fusion is fairly common, affecting 2-5% of babies and young girls aged between three months and six years. It is most common in girls between the ages of one and two.
The problem is rarely seen in girls after they begin puberty, because this is when they start to produce the hormone oestrogen. Oestrogen makes adhesions of the labia less likely to occur.
Why it happens?
It is not certain what causes labial fusion, but it usually occurs as a result of some irritation or inflammation (swelling) of the vaginal area, known as vaginitis. This can cause the inner lips of the vulva to become sticky and, without enough oestrogen in the body, the lips can stay stuck together and gradually become firmly attached.
How it is treated?
Treatment for labial fusion is not 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 rarely, surgical separation.
Surgery may be considered if:
an oestrogen cream or ointment does not work
a fusion is particularly thick and severe
there is 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 is used. To allow the labial edges to heal properly and prevent another labial fusion forming, you will be advised to apply an emollient cream, such as a nappy rash cream or Vaseline, to the labia for a few weeks afterwards.