Corpus Luteum Cysts During Pregnancy

Ultrasound technicians with pregnant woman

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During the second half of the menstrual cycle, immediately following ovulation, the empty ovarian follicle forms the corpus luteum. The corpus luteum releases estrogen as well as progesterone, which readies the uterus for implantation. If conception has occurred, the placenta will take over the function of progesterone production at around 12 weeks gestation.


Sometimes, a small fluid-filled sac known as a corpus luteal cyst, or corpus luteum cyst, can develop on the ovary during the first trimester of pregnancy. Corpus luteal cysts are a type of functional cyst.

While they vary in size, corpus luteal cysts are usually between 2 and 6 centimeters. Though they are not usually not any cause for concern, these cysts can lead to complications, though not typically related to pregnancy itself.

Risk Factors

Any women can get corpus luteal cysts, though they are more likely to develop in women taking medication to induce ovulation, like Clomid (clomiphene). These medications are usually prescribed by a doctor or midwife for women experiencing fertility problems, and for those with polycystic ovary syndrome (PCOS).

It's important to remember that since the corpus luteum is a normal part of the menstrual cycle, the type of functional ovarian cyst associated with them can also develop when you are not pregnant. You can also develop one even if you are not taking, or have never taken, medication to treat infertility.


Some women will notice one-sided pain during their cycle. The pain may be worrisome, especially if they are sexually active and concerned about the possibility of an ectopic or tubal pregnancy. This may prompt a visit to a doctor or midwife.

But in many cases, women who have a corpus luteal cyst do not experience any pain and may not even realize they have developed one. As a corpus luteal cyst will typically resolve on its own after a few menstrual cycles, and most women won't even realize it was ever there.


Corpus luteal cysts are typically diagnosed with an ultrasound. However, it may be a different type of ultrasound from the one most women expect. Cysts tend to be easier to see when an internal ultrasound, or a transvaginal ultrasound, is used.

While ultrasound may be ordered if you present symptoms, cysts are often found during a routine ultrasound for other purposes, both in women who are pregnant and those who are not.

(There are more opportunities to spot a corpus luteal cyst in a woman who's expecting, however, simply because she's having routine imaging as part of her prenatal care.)


A corpus luteal cyst is usually not a cause for concern. The cysts do not typically cause any complications during pregnancy, especially when they're discovered during the first trimester. If the cyst is potentially malignant, meaning it could grow or worsen, surgery may be required so as to avoid the risk of miscarriage. The most common symptom is a slight "twinge" of pain or mild tenderness.

If the cyst is causing pain, your doctor or midwife may prescribe pelvic rest or pain medications. In most cases, a corpus luteal cyst will resolve on its own.

Occasionally the cyst will rupture. The pain may increase when this happens but subside quickly, and pain medication and rest may be indicated. Less frequently, a corpus luteal cyst can cause the ovary to twist (torsion). This can be very painful and may require surgery to prevent further injury of the ovary.

Follow-Up and Recurrence

Your doctor or midwife may want you to have another ultrasound to check on the cyst if you continue to have symptoms. Otherwise, unless medical treatment is required, no follow-up will be needed after you have been diagnosed with a corpus luteal cyst.

If you have had a corpus luteal cyst in one pregnancy it does not necessarily mean you will develop one in another pregnancy. If you do develop cysts in subsequent pregnancies, they may or may not cause pain.

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