Near the introitus (that is, the opening of the vagina, but we need to talk in proper medical terms, this is not a cosmopolitan blog…), there are two glands, one on each side, just behind the labia. They are called Bartholin glands, named after a Danish anatomist, Caspar Bartholin in the 17th century.
They are small, you cannot palpate them and they produce a thick secretion, in order to lubricate and protect the lining of the vagina. They were thought to be related to lubrication during sexual arousal but, alas, their contribution is minimal. The glandular fluid enters the vaginal epithelium through a narrow tube, the duct.
Occasionally, for unknown reasons, the duct will get blocked and the sticky fluid will accumulate within the gland and the gland will become swollen. This is a bartholin cyst, and it affects 2% of women, mostly aged between 20 and 30. It may be asymptomatic, with just a local swelling and minor discomfort. If the cyst becomes infected, it then becomes an abscess, very tender indeed, the patient may find it difficult to walk and it needs urgent treatment.
It is not related to sexual intercourse and don’t blame your partner for transmitting the infection- there are many other reasons to blame your partner but not Bartholin issues.
It is equally not related to poor hygiene, tight underwear, sweating, swimming, the duct somehow decides to block itself and there is nothing you can do to prevent it from happening- frequent question when someone already suffered from one gland and wishes to avoid trouble from the other side in the future.
We tend to give a short course of antibiotic when a cyst appear, to prevent infection and this may delay the process but eventually things will get worse. The cyst will need to be drained and ideally a new duct should be surgically created. This procedure is called marsupialisation ( from Latin marsūpium, from Ancient Greek μαρσίππιον (marsippion), diminutive of μάρσιπος (marsipos, “pouch”))- yes, blame the Greeks for everything… This is a minor operation, it needs anaesthetic and it involves exteriorisation of the gland internal to the vaginal lining so that the fluid will readily be expelled in the future.
It is therefore a rather nasty situation but it is benign and will not affect your future sex life or fertility. Having said that, in older women (above the age of 40) we have the extremely rare bartholin gland cancer, so all labial swellings should be reviewed by a gynaecologist.
To summarise, when in pain, see your doctor and blame Caspar Bartholin …