Vaginal cysts form when fluid or tissue becomes trapped beneath the vaginal wall, creating a small, fluid-filled sac. The specific cause depends on the type of cyst, but the most common triggers are childbirth injuries, surgical scarring, blocked glands, and leftover embryonic tissue. About 1 in 200 women develop a vaginal cyst, most often in their 20s to 40s, though many never know because the cyst stays small and painless.
Inclusion Cysts: The Most Common Type
Inclusion cysts are the most frequently diagnosed vaginal cyst. They form when surface tissue gets pushed beneath the vaginal wall during an injury, then becomes sealed off. The trapped tissue continues to produce cells and fluid with nowhere to go, gradually forming a small pocket.
The two most common causes are vaginal childbirth and prior vaginal surgery. During delivery, small tears or episiotomies can heal in a way that buries bits of surface tissue under the lining. The same thing happens after surgical procedures like hysterectomy or vaginal repair, where the stitched tissue folds inward during healing. These cysts are typically small, painless, and found incidentally during a routine pelvic exam.
Bartholin Gland Cysts: Blocked Ducts
The Bartholin glands sit on either side of the vaginal opening, near the back, and produce a small amount of lubricating fluid. Each gland drains through a tiny duct. When that duct gets blocked, fluid backs up inside the gland and forms a cyst. These cysts average 1 to 3 cm, feel soft to the touch, and appear on one side only.
The blockage itself often results from friction during sexual intercourse, which can irritate and swell the duct opening shut. This is why Bartholin cysts are more common in sexually active women. A small Bartholin cyst may cause no symptoms at all. Larger ones can make sitting, walking, or sex uncomfortable.
The cyst becomes a bigger problem if bacteria get inside and cause an abscess. The most common bacteria involved are E. coli and staph, though respiratory bacteria like strep are increasingly found as well, possibly linked to oral sex. An abscess is noticeably different from a simple cyst: it’s painful, red, warm, and swollen, sometimes rapidly over a few days.
Gartner Duct Cysts: Leftover Embryonic Tissue
Before birth, a developing baby has a structure called the Gartner duct, which plays a role in the urinary and reproductive system as it forms. In most cases this duct disappears after birth. Sometimes, though, small remnants persist along the vaginal wall. These remnants can collect fluid over time and develop into a cyst years or even decades later.
Gartner duct cysts typically appear along the front and side walls of the vagina, roughly at the 11 o’clock and 1 o’clock positions. They can extend deep into the vaginal wall. Because these cysts stem from embryonic development rather than injury or infection, there’s nothing a person could have done to prevent them. They’re simply a quirk of how the body developed before birth.
Müllerian Cysts
Müllerian cysts also originate from embryonic tissue, specifically from the structures that eventually form the uterus, fallopian tubes, and upper vagina during fetal development. When small bits of this tissue remain in the vaginal wall, they can accumulate fluid and form a cyst. Like Gartner duct cysts, these are present from birth in a sense, but they may not become noticeable until adulthood. They can appear anywhere along the vaginal wall and are usually filled with mucus rather than clear fluid.
Less Common Causes
A few other structures near the vaginal opening can produce cysts. The Skene glands, located near the urethra, have small ducts that can become blocked in the same way Bartholin ducts do. Skene duct cysts are rare but noteworthy because a large one can press on the urethra and interfere with urination. Mucous cysts of the vestibule, which form from blocked mucus-secreting glands near the vaginal entrance, tend to stay under 2 cm and rarely cause symptoms.
When Cysts Cause Symptoms
Most vaginal cysts remain small and painless. Many women discover them only when a doctor feels a smooth, round lump during an exam. Whether a cyst causes problems comes down to its size, location, and whether it becomes infected.
Small cysts, particularly those under 1 to 2 cm, are almost always asymptomatic. As a cyst grows larger, it can create a sense of pressure or fullness. Bartholin cysts that reach the upper end of their size range may cause pain during sex, discomfort while sitting, or a visible bulge near the vaginal opening. Gartner duct cysts that extend deeper into the wall sometimes produce a dragging sensation.
Infection changes the picture entirely. An infected cyst swells rapidly, becomes tender, and can develop into an abscess filled with pus. This is most common with Bartholin cysts but can happen with any type. The shift from painless lump to painful, inflamed mass usually happens over a matter of days.
How Doctors Identify the Type
Location is the biggest clue. Bartholin cysts appear in the lower back portion of the vaginal opening. Gartner duct cysts sit along the front and side walls, higher up. Inclusion cysts tend to cluster near episiotomy scars or surgical sites on the back wall. A doctor can often identify the type based on a physical exam alone.
When the diagnosis is uncertain, or when a cyst appears in a woman over 40, doctors may recommend imaging or a biopsy. This isn’t because cysts are dangerous in themselves, but because in rare cases a solid mass can mimic the feel of a cyst. Ruling out other possibilities is a straightforward step that provides peace of mind.
What Determines Whether Treatment Is Needed
Asymptomatic cysts generally require no treatment. A small, painless cyst found during a routine exam is typically left alone and monitored over time to make sure it isn’t growing. Many of these never change.
Treatment becomes relevant when a cyst causes persistent discomfort, interferes with daily activities or sex, or becomes infected. For Bartholin cysts, the goal is to restore drainage from the blocked gland rather than simply removing the cyst, since the gland still serves a function. For inclusion cysts and other types, removal of the cyst wall is straightforward when needed. Infected cysts that have formed abscesses need to be drained, and sometimes antibiotics are involved to clear the infection.
Recurrence is possible, particularly with Bartholin cysts. The duct can re-block after treatment, leading to a new cyst in the same spot. This is more of an annoyance than a serious concern, but it’s worth knowing if you’ve had one before.