Yes, it is common to have ovarian cysts while pregnant, and they are frequently discovered during routine prenatal imaging. An ovarian cyst is a fluid-filled sac that develops on or within an ovary. While the discovery can be concerning, the vast majority of cysts found during gestation are harmless and resolve without intervention. Understanding their formation and monitoring is important.
Hormones and Expected Cyst Formation
The most common type of ovarian cyst encountered in early pregnancy is the functional corpus luteum cyst. After ovulation, the remaining follicle transforms into the corpus luteum, which produces high levels of hormones. This structure secretes progesterone, necessary to thicken the uterine lining and sustain early pregnancy until the placenta is fully developed.
The pregnancy hormone human chorionic gonadotropin (hCG) signals the corpus luteum to continue producing progesterone. If fluid accumulates within this structure, it becomes a corpus luteum cyst. This cyst is a normal part of supporting the pregnancy and is not considered pathological. These functional cysts typically regress and disappear by the beginning of the second trimester (around 14 to 20 weeks), when the placenta takes over hormone production.
Pre-Existing and Pathological Cysts
Not all cysts found during pregnancy are the expected functional type; some may be pre-existing or develop independently of pregnancy hormones. These are broadly categorized as pathological cysts, which warrant closer attention. Dermoid cysts (mature teratomas) contain various tissue types such as hair, fat, or skin cells. Endometriomas, or “chocolate cysts,” are filled with old, dark blood and are a manifestation of endometriosis, where tissue similar to the uterine lining grows on the ovary.
Cystadenomas are benign tumors that grow on the surface of the ovary and can sometimes reach a very large size. While these non-functional cysts are generally benign, pregnancy can sometimes cause them to grow due to increased blood flow. The presence of a pathological cyst does not usually threaten the pregnancy, but its nature and size must be assessed to rule out rare complications or malignancy.
Identifying Cysts and Monitoring During Pregnancy
Ovarian cysts are most frequently detected incidentally during a routine first-trimester ultrasound. Up to four percent of pregnant individuals may be found to have an ovarian mass during this standard imaging. Most cysts, particularly the small functional ones, are asymptomatic.
When symptoms do occur, they are typically mild and may include a dull ache, a feeling of heaviness, or pelvic pressure, especially if the cyst is large. Monitoring involves serial ultrasounds to track the cyst’s size, shape, and internal characteristics. A simple, unilocular cyst smaller than five centimeters often requires no further follow-up beyond routine prenatal care, as it is a functional cyst that will resolve spontaneously. Cysts that are larger or have complex features, such as solid components or internal divisions, may require more frequent ultrasound checks, often four weeks apart, to evaluate changes.
Treatment Pathways and Complications
For the majority of cysts that are small, simple, and asymptomatic, the standard approach is watchful waiting. This conservative management allows time for the cyst to resolve. Pain relief medication, determined safe for use in pregnancy, may be prescribed for individuals experiencing mild discomfort.
Intervention becomes necessary if the cyst is suspicious for malignancy or if acute complications develop. One such complication is ovarian torsion, a surgical emergency where the ovary twists on its supporting ligaments, cutting off its blood supply. Torsion causes a sudden onset of severe, sharp, unilateral pelvic pain, often accompanied by intense nausea and vomiting. Cyst rupture is another complication, which can cause sudden, sharp pain due to internal bleeding or irritation, but often resolves with conservative management and pain control. If surgery is required, it is generally delayed until the second trimester (16 to 20 weeks), as this period is considered the safest for the mother and the developing fetus.