Corpus luteum cysts during pregnancy are common ovarian cysts formed when the corpus luteum (cluster of cells in which the egg seals itself) fails to shrink after about 12 weeks of pregnancy, causing it to fill with fluid. The corpus luteum produces progesterone that helps prepare the endometrial lining for implantation. These cysts are common during pregnancy and not usually troublesome. But, if these are not treated immediately, they might continue to grow, rupture and twist, giving rise to complications in the pregnancy (1) (2) (3).
Read on to know about the symptoms, causes, and treatments for corpus luteum cyst in pregnancy.
Are Corpus Luteum Cysts Normal In Pregnancy?
Corpus luteal cysts are among the most common functional ovarian cysts in pregnancy. When the corpus luteum cyst develops into a luteal cyst, it continues to produce progesterone to support the pregnancy and is mostly harmless. The cyst gradually disappears at the start of the second trimester.
Corpus Luteum And The Menstrual Cycle
- Follicular phase: The follicular phase begins on the first day of the menstrual period and continues for around 14 days. During this phase, the pituitary gland secretes a high level of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) into the blood supply, inducing the maturation of the follicles containing eggs.
One of the follicles, known as the dominant follicle, grows faster than the others and causes an increase in estrogen levels by day seven. The estrogen then suppresses the level of FSH and increases that of LH, thereby marking the beginning of the ovulatory phase.
- Ovulatory phase: This phase occurs on day 13 or 14 of the menstrual period. As the level of LH in the blood increases, the egg in the dominant follicle completely matures and releases. The follicle then contracts into a cluster of cells called the corpus luteum, marking the start of the luteal phase.
- Luteal phase: This phase usually begins on day 15 with the corpus luteum producing an increased level of progesterone. It induces the development of the uterus’s endometrium lining to implant the sperm-fertilized egg and helps sustain the pregnancy.
The corpus luteum produces progesterone up to ten weeks of pregnancy, after which it shrinks and eventually disappears. If pregnancy does not occur, the progesterone and estrogen levels gradually decrease, causing the endometrium lining to fall off, which induces menstrual bleeding.
Symptoms Of Corpus Luteum Cysts
- Constant pelvic pain or pain before and at the beginning of a period
- Pain during intercourse
- Unusual bloating or swelling of the abdomen
- Unexplained weight gain
- Abnormal vaginal bleeding and heightened menstrual cramps
- Difficulty or pain during urination and bowel movements
- Frequent urination
Identifying Corpus Luteum Cysts
A corpus luteum cyst is usually detected through a transvaginal ultrasound using a transducer. When placed in the vagina, the transducer produces sound waves that help visualize the ovary and the cysts, if any. In addition, a transvaginal ultrasound enables the doctors to identify the cyst’s location, size, and shape and determine if it is fluid-filled or solid (8).
This cyst can also be detected through a transabdominal ultrasound, where the transducer is placed on the abdomen to visualize the cyst (9).
Risk Factors Of Corpus Luteum Cyst
- Fertility medications: The most commonly prescribed fertility drug is clomiphene, given to women facing difficulty in conceiving or women with PCOS. PCOS interferes with the production of the pregnancy hormones that release the eggs from the follicles. These medications could create a hormonal imbalance resulting in an ovarian cyst.
- Endometriosis: This condition causes the tissue lining the uterus to grow on its outside. Women who have endometriosis are at a higher risk of developing a corpus luteal cyst.
- Pregnancy: Pregnant women may be at greater risk of the cyst; however, a corpus luteum cyst can also develop in nonpregnant women.
- Ectopic pregnancy: The condition where the egg implants outside of the uterus, either in the fallopian tubes or the ovary. The probability of developing a corpus luteum cyst may be higher in women with ectopic pregnancy.
When To Seek Emergency Care
Corpus luteum cysts generally do not require any medical attention and disappear over time. However, if you experience acute abdominal pain, abnormal bleeding, and high temperature, check with your healthcare provider as these could be symptoms of an ovarian cyst rupture or a torsion (7).
Treatment For Corpus Luteum Cyst
- Observation: For mild symptoms that do not cause any discomfort, your healthcare practitioner may recommend regular observation through routine ultrasounds and physical examination until the symptoms subside.
- Oral contraceptives: Birth control pills may be prescribed, which can help prevent the risk of recurrence of the ovarian cyst. Your healthcare practitioner may also prescribe pain relief medication.
- Laparoscopy: In severe pain or ovarian cyst rupture or torsion, laparoscopic surgery may be recommended. In this surgery, a tube fitted camera, inserted through a small cut in the lower abdomen, is used to visualize and remove the cyst.
Corpus Luteum Cyst Rupture During Pregnancy
Cysts can sometimes rupture and cause acute pain in the lower abdomen. The doctor may prescribe certain pain relief medications, following which the cyst usually heals.
A ruptured cyst can sometimes lead to hemoperitoneum, a condition characterized by a blood-filled peritoneal cavity. The condition generally requires a laparoscopic or laparotomy surgery based on its severity (10) (11).
Corpus Luteum Cyst Torsion During Pregnancy
A growing corpus luteum cyst may add weight to the ovary, causing it to twist on itself or the surrounding tissues. When an ovarian torsion occurs, the blood supply to the ovary is obstructed causing severe pain and sometimes vomiting and may require immediate surgery (12).
Frequently Asked Questions
1. Can a corpus luteum cyst cause miscarriage?
Typically, a corpus luteum cyst does not interfere with the pregnancy but helps sustain it by producing the progesterone hormone and disappears by the second trimester. However, a corpus luteum cyst can become hemorrhagic, where blood fills the cyst cavity, causing acute abdominal pain. Seeking medical attention helps prevent the risk of miscarriage (13).
2. Can a corpus luteum cyst be cancerous?
A corpus luteum cyst, being a functional cyst, is usually not cancerous. However, some conditions associated with corpus luteum cysts, such as endometriosis and PCOS, are associated with an increased risk of developing ovarian cancer. Further, ovarian cancer can sometimes show as a luteal cyst. Your doctor may conduct different tests based on the cyst’s size and symptoms to identify any chance of malignancy (14) (15).
3. Can a corpus luteum cyst cause a positive pregnancy test?
Pregnancy can cause corpus luteum cysts. However, a corpus luteum cyst can sometimes give a false positive pregnancy result due to increased hCG levels. Your healthcare practitioner may carry out additional tests, such as blood tests, for confirmatory results (16) (17).
4. What does the corpus luteum look like on an ultrasound?
A corpus luteum is a thick-walled cyst having a typical ‘ring of fire’ peripheral vascularity on color Doppler ultrasound. It is usually seen with a crenulated (ridge-like) inner margin (18).
5. Can a corpus luteum cyst be mistaken for a gestational sac?
The corpus luteum may be confused with the ectopic pregnancy’s gestational sac. However, a reliable way of distinguishing it from ectopic pregnancy is by identifying the location of the lesion. Corpus luteum arises from the ovary, while most ectopic pregnancies are tubal (19).
Corpus luteum cyst is not a condition of concern and mostly disappears with time. However, to avoid complications, you should be aware of the symptoms of corpus luteum cysts and seek immediate medical attention for proper diagnosis and timely treatment.
- Corpus luteal cysts are harmless when they turn into a luteal cyst as they can produce progesterone.
- Transvaginal and transabdominal ultrasounds can help detect corpus luteum cyst size, shape, and location.
- Ovarian cyst symptoms include pelvic pain during period, pain during intercourse, unusual swelling or bloating of the abdomen, etc.
- Corpus luteal cyst.
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- Kishore Pandit et al.; (2018); Massive Hemoperitoneum from a Ruptured Corpus Luteal Cyst.
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- Mykhailo V Medvediev et. al.; (2020); Hemorrhagic corpus luteum cyst: Clinical management update.
- Ovarian Cysts: What Are the Risks?
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- Robert Lee et al.; (2018); Diagnosing ectopic pregnancy in the emergency setting.