Corpus Luteum Cyst

A corpus luteum cyst is a normal, harmless, fluid-filled mass that forms on your ovaries. The corpus luteum is a group of cells that takes shape after your ovary releases an egg (ovulation) each month. The sac surrounding the cells contains fluid, which makes up the cyst.

Your corpus luteum produces a hormone called progesterone that supports your uterus to prepare for a possible pregnancy. It breaks down when it’s no longer needed. Sometimes, the sac will fill with blood if a small blood vessel on the surface of the ovary is disrupted during ovulation. Blood-filled corpus luteum cysts can cause pain and take longer to go away.

Anyone who menstruates can get a corpus luteum cyst. Your healthcare provider is more likely to find one if you’re pregnant because they last a little longer to support the pregnancy. They’re usually painless, so most people don’t even know they have one. They often show up as part of a routine pregnancy ultrasound.

Symptoms of a corpus luteum cyst

You likely won’t know you have one because most are small and don’t cause symptoms. If the cyst is blood-filled, you may have pressure or cramping for a few weeks. Rarely, the cyst can get large enough to twist the ovary (ovarian torsion) or leak blood into your abdomen. If one of those things happens, you may have the following symptoms:

• Severe pelvic pain
• Nausea/vomiting
• Weakness or dizziness

You should call your provider if you have any of these symptoms.

Corpus luteum cyst causes

A corpus luteum cyst forms in your ovaries when your corpus luteum fills with fluid and expands instead of breaking down.

Each menstrual cycle, a sac in one of your ovaries called a follicle creates and releases an egg. Soon after, your corpus luteum forms from the wall of the follicle. It releases progesterone, which makes the lining of your uterus thicker so that a fertilized egg can take hold there. It creates a healthy environment inside your uterus where the fertilized egg becomes a fetus.

Your corpus luteum goes away when the placenta takes over making progesterone to support a pregnancy (usually around the 12th week). If the egg doesn’t get fertilized, your corpus luteum usually goes away 10 to 12 days after ovulation.

You shouldn’t expect a corpus luteum cyst to impact your life at all. Complications with these cysts can happen, but they’re rare.

How doctors diagnose it

These types of cysts are usually found by accident during an ultrasound. A corpus luteum cyst is usually between 1 and 3 centimeters (cm) in size. Your provider may see it on your ovary in the first trimester or during a pelvic ultrasound in the second half of your menstrual cycle.

How is it treated?

Chances are you won’t need treatment for a corpus luteum cyst. If you’re pregnant, it will probably go away in your second trimester. If you’re not pregnant, the cyst will break down a few weeks after ovulation.

In the meantime, your provider can offer treatment to help you manage any symptoms. Your provider may recommend:

• Using a heating pad (if you aren’t pregnant)
• Pain medications
• Pausing sexual intercourse (if it’s worsening your pain or the cyst is unusually large)

If the cyst gets so big that the ovary twists, which could harm your ovary or pose risks to your pregnancy, your provider may remove your cyst. This is rare.

When should I see my healthcare provider?

You should seek medical care if your cyst bursts and causes severe pain. Also, you should seek emergency care if it grows so big that it twists your ovary.

Get help right away if you notice these symptoms:

• Persistent nausea and vomiting with pelvic pain
• Feeling light-headed or dizzy (like you’re about to faint)
• Stabbing pain in one side of your abdomen

These warning signs are important. Keep in mind, though, that corpus luteum cysts usually disappear without causing problems.

Can I get pregnant with a corpus luteum cyst?

Yes. They’re a normal part of early pregnancy. But sometimes, a large or persistent corpus luteum cyst can cause discomfort. If this is the case, your healthcare provider will talk to you about what comes next.