What size of ovarian cyst is dangerous to health?

Ovarian cysts are common in women of all ages, and while most are harmless, some can grow to a size that causes complications. But what size of ovarian cyst is dangerous? In this article, we break down everything Australian women need to know—based on current medical guidance, local healthcare access, and the symptoms that should never be ignored.

Types of ovarian cysts

Before elaborating on ovarian cyst sizes, which may prove dangerous, first, it would be important to know the varieties of ovarian cysts. The majority of ovarian cysts are benign. They do not need treatment since they are usually non-cancerous. Types of ovarian cysts include:

1. Functional Cysts: These are the most common and often present during the menstrual cycle. These are usually non-threatening and disappear spontaneously in several months. Examples of functional cysts are as follows:

• Follicular Cysts: A cyst develops due to the non-expulsion of an egg, leaving the sac, which further continues to increase in size.
• Corpus Luteum Cysts: These occur after ovulation when the follicle fails to collapse after the release of the egg and fluid starts collecting.

2. Dermoid Cysts: They are less common and can be composed of a variety of tissues, including hair, skin, and even teeth. Dermoid cysts are typically benign, but they may cause problems when they become too large.

3. Endometriomas: This is a condition where tissue that is similar to the lining of the uterus forms on the ovaries. Most of the time, it has been associated with endometriosis, in which uterine tissue develops outside the uterus.

4. Cystadenomas: These cysts arise from the cells lining the surface of the ovaries. They can fill with a watery or mucus-like fluid. Though generally benign, they can become quite large in size.

5. Polycystic Ovarian Syndrome (PCOS): This is not a single cyst but a condition in which many small cysts develop on the ovaries. PCOS can cause hormonal imbalances and problems with fertility but does not usually involve large cysts that are dangerous.

What size of ovarian cyst is dangerous

Ovarian cysts differ in size: some are quite small, less than a few millimeters in size, and others are huge, several centimeters in diameter. The risk factor is, in part, determined by the size of the cyst. For easy reference, here are the sizes and risks associated with each:

1. Small cysts (Less than 5 cm)

Most ovarian cysts fall under this category. Functional cysts, which are the most common type, are usually less than 5 cm in size. These cysts are not dangerous and rarely cause symptoms. They tend to resolve on their own within a few months without medical intervention. In many cases, a doctor may monitor these cysts over time to ensure they don’t grow or cause complications.

• When to see a doctor: If you are experiencing pain, bloating, or any other unusual symptoms with a small cyst, it is worth discussing it with your healthcare provider. Small cysts are usually benign, but they can still cause discomfort or other issues.

2. Medium-sized cysts (5 cm – 7 cm)

Those between 5 cm and 7 cm in diameter are usually not cancerous, but they can produce symptoms like pelvic pain, bloating, or changes in menstruation. Larger cysts in this range may twist or rupture, causing worse problems. A twisted ovarian torsion cuts off the blood supply to the ovary and creates extreme pain, requiring immediate medical care.

• When to get medical care: If a cyst of this size causes sudden, sharp pain, fever, or nausea, one needs to get medical attention as soon as possible. This might indicate a ruptured cyst or torsion of the ovary or other complications.

3. Large cysts (>7 cm)

Cysts larger than 7 cm are concerning and are usually referred for further investigation. Large-sized cysts could cause many significant symptoms such as pelvic pain and bloating, or pressure in the vicinity of organs like the bladder and bowel.

• These large cysts are at an increased risk for rupture, twisting, and infections, all which can have dire health implications. In some instances, such cysts might need to be removed surgically when they have symptoms that are recurring or even pose a threat to ovarian cancer.
• Seek immediate medical attention if you suspect a large cyst is more than 7 cm or experience severe abdominal pain, pain during urination, vomiting, or fever. Your healthcare provider may do some imaging tests, like ultrasound or CT scans to check on the cyst and provide recommendations for appropriate actions.

What makes large cysts dangerous?

1. Ovarian torsion

When a large cyst causes the ovary to twist, it cuts off its blood supply. This condition is called torsion and is a medical emergency. It causes sudden, sharp pelvic pain and often requires urgent surgery.

2. Cyst rupture

As cysts grow larger, they become more prone to bursting. A rupture can cause internal bleeding, severe pain, and in some cases, infection.

3. Pressure on nearby organs

Larger cysts may press on the bladder, bowels, or nerves, causing problems like frequent urination, constipation, and lower back pain.

4. Suspicion of malignancy

Although most ovarian cysts are benign, complex or large cysts—especially in postmenopausal women—may raise concern for ovarian cancer. In these cases, blood tests and surgery may be used to rule out malignancy.

Symptoms to watch out for

Regardless of size, certain symptoms may indicate a problem. See your GP immediately if you experience:

• Sudden, severe abdominal or pelvic pain
• Pain during sex
• Ongoing bloating or swelling
• Difficulty emptying your bladder
• Changes in menstrual patterns
• Nausea or vomiting, especially with pain

These symptoms could suggest torsion, rupture, or a growing cyst.

When is surgery required?

Surgery is usually advised when:

• The cyst is larger than 10 cm
• It doesn’t shrink over time
• It causes persistent pain
• There is a risk of rupture or torsion
• Cancer cannot be ruled out

Types of surgery:

• Laparoscopy – minimally invasive; ideal for smaller, benign cysts
• Laparotomy – open surgery for larger or potentially cancerous cysts

Both procedures are available across Australian public and private hospitals. Medicare can cover a significant portion of the cost, and private health insurance may reduce waiting times.

Conclusion

Understanding what size of ovarian cyst is dangerous empowers women to take their reproductive health seriously. If you’re living in Australia and have been diagnosed with a cyst—or are experiencing symptoms—don’t hesitate to seek medical advice. Early intervention can prevent complications and bring peace of mind.

Your health matters, and with the right information and access to care, you can make confident decisions for your wellbeing.