The Fertility Notes

Ovarian Cysts: Types, Warning Signs and Fertility

Illustration of a woman holding her lower abdomen with an enlarged diagram of ovarian cysts and other masses.
Illustration of a woman holding her lower abdomen with an enlarged diagram of ovarian cysts and other masses.

Ovarian cysts are not one diagnosis. Some are temporary changes related to ovulation; others include endometriomas, dermoid cysts and benign or malignant tumors. Most cysts are benign, but symptoms, ultrasound features, age and menopausal status guide assessment. For someone planning pregnancy, the possible benefit of surgery must also be weighed against its effect on healthy ovarian tissue.

  • A broad spectrum of pathology: From functional cysts that appear and resolve during normal ovulation to endometriomas, teratomas, and true benign or malignant neoplasms
  • Different causes demand different treatments: Even under the shared label of an “ovarian cyst,” management diverges completely; women seeking fertility must approach surgery with heightened caution
  • An ultrasound finding does not automatically equal cancer: Risk stratification relies on size, architecture, Doppler blood flow, and menopausal status

When a physician pauses during a pelvic ultrasound and mentions, “There is something visible on your ovary,” many women immediately fear the worst: cancer.

In reality, lesions discovered in the ovary span a far broader and more nuanced spectrum. Some are simple fluid-filled water cysts that emerge during this month’s ovulation only to resolve by the next; others are endometriomas filled with degraded, pooled blood, dermoid cysts containing fat and hair, benign neoplasms that grow independently of menstrual cycles, or, in rare instances, malignant tumors.

While they all appear as “an ovarian mass or cyst” on the surface, their underlying biological causes and clinical management could not be more different.

Functional ovarian cysts: when they may resolve

The most common findings are functional ovarian cysts.

Every month, the ovaries recruit and mature follicles to release an egg. If a dominant follicle fails to rupture and release its oocyte, it can continue to expand, forming a follicular cyst. Conversely, if the corpus luteum—the temporary endocrine structure formed after ovulation—accumulates fluid or blood instead of regressing, it becomes a corpus luteum cyst.

Most functional cysts are benign and resolve over several weeks to a few months. A simple, smooth-walled cyst in a premenopausal woman may therefore be monitored with follow-up ultrasound instead of being removed immediately. The timing and need for follow-up depend on its appearance, size, symptoms and the patient’s circumstances; waiting until the next cycle is not appropriate for every ovarian mass.

Endometriomas: chocolate cysts and fertility decisions

For women planning a pregnancy, the ovarian endometrioma is of paramount clinical importance.

Commonly called a “chocolate cyst,” an endometrioma is an ovarian cyst associated with endometriosis, in which tissue resembling the uterine lining occurs outside the uterus. Repeated bleeding and retained, degraded blood give the cyst its characteristic thick, dark-brown contents. This appearance explains the nickname, although endometrioma formation is more complex than simply trapping one menstrual period’s blood.

Endometriomas are associated with local inflammation and oxidative stress, and may affect surrounding ovarian tissue and fertility. The impact varies between patients; their presence does not establish that an ovary cannot respond to stimulation. See research comparing egg retrieval from ovaries with and without an endometrioma.

Cystectomy can also remove or injure adjacent healthy ovarian tissue and follicles, reducing ovarian reserve and AMH. The extent of any decline varies. Decisions therefore need to balance pain, cyst characteristics and size, baseline ovarian reserve, previous surgery and IVF plans. ESHRE does not recommend routine endometrioma surgery before assisted reproduction solely to improve live birth rates: benefit has not been demonstrated and surgery is likely to harm reserve. Surgery may still be considered for other reasons, including pain or difficulty accessing follicles.

Hemorrhagic cysts: bleeding inside a cyst

Hemorrhagic cysts are another frequent finding. They occur when a fragile blood vessel ruptures within a physiological cyst—most often a corpus luteum—during or shortly after ovulation, filling the cavity with blood.

On an ultrasound monitor, the organizing clot and fibrin strands create an internal reticular pattern (often described as a “spiderweb” or “fishnet” appearance) that can look alarming to an untrained eye. In the majority of stable cases, however, the trapped blood is gradually broken down and reabsorbed by the body, allowing the cyst to resolve naturally over one to two cycles.

The primary risk arises if a hemorrhagic cyst ruptures and bleeds heavily into the peritoneal cavity. Significant intra-abdominal hemorrhage can trigger sudden, severe pelvic pain, dizziness, cold sweats, and peritoneal irritation, requiring prompt emergency evaluation.

Dermoid cysts and the risk of ovarian torsion

Perhaps the most startling lesion by name and content is the mature cystic teratoma, historically known as a dermoid cyst.

Arising from pluripotent germ cells responsible for generating gametes, these tumors have the biological capacity to differentiate into various germ layers. Consequently, their internal cavity can contain sebaceous fluid, adipose tissue, skin fragments, strands of hair, and occasionally calcified structures like bone or teeth. While this description sounds menacing, mature cystic teratomas are almost overwhelmingly benign.

A dermoid cyst, particularly a larger one, can be associated with ovarian torsion: the ovary twists around its supporting structures and its blood supply is compromised. Sudden severe pain on one side of the lower abdomen, often with nausea and vomiting, requires urgent assessment; pain can also be intermittent. Suspected torsion is a surgical emergency, and prompt detorsion aims to preserve viable ovarian tissue. It should not be assumed that all blood flow stops instantaneously or that the ovary must always be removed.

Serous and mucinous cystadenomas

Certain benign tumors grow independently of the ovulatory cycle. The most common varieties are serous cystadenomas and mucinous cystadenomas.

Serous cystadenomas are filled with thin, watery fluid, whereas mucinous cystadenomas contain thick, gelatinous mucus and have a propensity to grow to substantial sizes—sometimes spanning 15 to 20 centimeters or more. In their early stages, they produce virtually no symptoms, often going unnoticed until a patient presents with abdominal distension, pelvic fullness, or localized pressure on the bladder and bowel.

Unlike functional cysts, cystadenomas do not regress on their own. Depending on their diameter, structural complexity on imaging, patient age, and symptomatic burden, they are managed via periodic ultrasound surveillance or elective surgical excision.

Why PCOS follicles are different from ovarian cysts

Due to its terminology, Polycystic Ovary Syndrome (PCOS) is frequently confused with true ovarian cysts.

The multiple small structures seen on ultrasound in polycystic ovarian morphology are small follicles, rather than the separate pathological cysts described above. The classic “string-of-pearls” pattern can occur, but it is not required in every patient and should not be treated as an ovarian tumor.

PCOS is a heterogeneous endocrine and metabolic syndrome, not a neoplasm. It can involve ovulatory dysfunction, hyperandrogenism and polycystic ovarian morphology; insulin resistance is common, but neither it nor elevated luteinizing hormone is a universal diagnostic requirement. In adults, diagnosis generally requires two of the three core features after other causes are excluded; ovarian morphology is not required when ovulatory dysfunction and hyperandrogenism are both present. This is distinct from a solitary ovarian cystic lesion.

How clinicians assess ovarian cancer risk

The most critical entity to rule out when evaluating an adnexal mass is a malignant neoplasm. However, it is vital to remember that an ultrasound notation of “an ovarian mass” is far from an immediate cancer diagnosis.

Sonographers and gynecologists systematically stratify malignancy risk using standardized imaging guidelines (such as the IOTA simple rules or O-RADS scoring). Key variables include:

  • Patient Context: Menopausal status and age (the baseline probability of malignancy increases significantly post-menopause).
  • Internal Architecture: Solid tissue, papillary projections, irregular walls or septa, and the overall structure of the mass.
  • Vascularity: The presence, degree and distribution of blood flow on color Doppler, interpreted with the other imaging features.
  • Secondary Findings: Free peritoneal fluid (ascites) or peritoneal nodularity.

Suspicious imaging features may lead to specialist assessment and selected additional tests. Serum markers such as CA-125 or HE4, and a combined risk tool such as ROMA, may contribute in appropriate clinical settings, but they do not diagnose or exclude cancer on their own. MRI may help characterize an indeterminate mass; CT is more often used when assessing the extent of suspected malignancy. The choice is individualized rather than an automatic requirement for every complex cyst.

Evidence indicates that many high-grade serous cancers classified as ovarian cancers begin in the fallopian tube, particularly the fimbrial end, and serous tubal intraepithelial carcinoma (STIC) is a recognized precursor. This has informed discussion of opportunistic salpingectomy: removing the tubes while preserving the ovaries during an operation already being performed for another indication. Counseling must address benefits, remaining cancer risk and fertility consequences; bilateral salpingectomy is not a routine response to a cyst in someone who wishes to conceive naturally.

Choosing treatment while considering fertility

The label “ovarian cyst” alone does not establish its cause or the treatment it needs.

The first step is to assess the likely nature of the mass: simple fluid, blood, an endometrioma, fatty tissue or a neoplasm. Ultrasound can suggest a diagnosis, but definitive histology may be available only if tissue is removed. The ovary changes throughout the menstrual cycle, and some functional lesions appear and later resolve. What matters is the combination of likely lesion type, symptoms, risk features and behavior over time.

For women planning a pregnancy or assisted reproduction, a surgical decision should not rest on centimeters alone. Two masses of the same diameter may require different management depending on their likely type, imaging features, relationship to healthy ovarian tissue, baseline reserve and egg retrieval plans. Ovarian reserve after different endometrioma procedures is one of the issues to discuss when weighing treatment.

The clinical objective is to manage symptoms and disease safely while preserving healthy ovarian tissue whenever appropriate. If malignancy is suspected, timely specialist evaluation remains essential; fertility goals should be part of that discussion.

A useful question to bring to the consultation is: “How much healthy ovarian tissue can we preserve while treating this lesion safely?”

※ This article draws on ACOG information and guidance on ovarian cysts and adnexal masses, the ESHRE Endometriosis Guideline, and the additional professional guidance linked below. It does not replace individualized clinical diagnosis or medical care. Treatment decisions should be discussed with a qualified gynecologist or reproductive endocrinologist.

※ The images associated with this article were generated using generative AI (ChatGPT, OpenAI) as illustrative visual references and do not depict real individuals.

Clinical sources

Copyright © 2026 Fertility Information TokTok Fertility News | THE FERTILITY NOTES. All rights reserved. Unauthorized republication, reproduction, redistribution, scraping, AI training, and data use of any content, including articles, photographs, and images, are strictly prohibited. Violations may result in legal liability.