Several factors can make ovarian cysts grow larger, become more painful, or lead to complications like rupture and torsion. The most common culprits are hormonal imbalances, insulin resistance, pelvic infections, and environmental chemical exposure. Most functional cysts resolve on their own within a few weeks to a couple of months, but certain conditions can stall that process or actively make things worse.
Hormonal Imbalances That Fuel Cyst Growth
Ovarian cysts are fundamentally driven by hormones. Every month, your ovaries produce a small fluid-filled sac (a follicle) that releases an egg during ovulation. When hormone levels are disrupted, that follicle may not release the egg at all, instead growing into a cyst. The corpus luteum, the structure left behind after ovulation, can also fill with fluid and become a cyst if hormonal signaling goes wrong.
Elevated levels of luteinizing hormone (LH) and free testosterone are particularly problematic. In women with polycystic ovary syndrome (PCOS), this pattern creates a state of chronic anovulation where immature follicles accumulate on the ovaries rather than completing their cycle. Under current diagnostic guidelines, 20 or more follicles on at least one ovary is the threshold for polycystic ovarian morphology. These aren’t large individual cysts but a buildup of small ones that reflects an ongoing hormonal disruption rather than a one-time event.
Estrogen receptor function also plays a direct role. Animal studies show that when certain estrogen receptors are impaired, ovaries develop multiple hemorrhagic and cystic follicles with no ovulation occurring at all. This suggests that it’s not just the amount of estrogen or progesterone circulating in your body that matters, but how well your tissues respond to those hormones.
How Insulin Resistance Makes Cysts Worse
High insulin levels are one of the most overlooked drivers of worsening ovarian cysts. When your body becomes resistant to insulin, it compensates by producing more. That excess insulin directly stimulates the ovaries to pump out more androgens (male-type hormones like testosterone). At the same time, high insulin reduces the liver’s production of sex hormone-binding globulin (SHBG), a protein that normally keeps testosterone in check. The result is more free testosterone circulating in your blood, which disrupts normal follicle development and contributes to cyst formation.
This creates a cycle that’s hard to break. Elevated insulin stimulates the pituitary gland to release even more LH, which further ramps up androgen production from the ovaries and adrenal glands. Follicles that should mature and release an egg instead stall partway through development, accumulating as cysts. For women with PCOS, managing insulin resistance through diet, exercise, or medication can be one of the most effective ways to slow this process down.
Fertility Treatments and Ovarian Hyperstimulation
Fertility medications, particularly injectable hormones used during IVF, can cause rapid cyst growth and a condition called ovarian hyperstimulation syndrome (OHSS). Injectable fertility drugs are significantly more likely to cause this than oral options. The risk spikes when an HCG “trigger shot” is given to prompt egg release, because it can cause the ovaries to swell dramatically and fill with fluid.
If you’re undergoing fertility treatment, your provider will typically use the lowest effective dose to minimize this risk. Alternatives to HCG triggers have been developed specifically to reduce OHSS. If you’ve had ovarian cysts before or have PCOS, you’re at higher risk for hyperstimulation, which is worth discussing with your fertility specialist before starting treatment.
Pelvic Infections and Inflammation
Pelvic inflammatory disease (PID), usually caused by sexually transmitted infections like gonorrhea or chlamydia, raises the risk of developing infected ovarian cysts. These cysts essentially become abscesses filled with bacteria. The infection doesn’t just make existing cysts more painful; it transforms them into a more dangerous type.
If an infected cyst ruptures, the bacteria can spread into the bloodstream and trigger sepsis, a life-threatening immune response. This is one of the first things clinicians assess when someone comes in with sudden, severe pelvic pain from an ovarian cyst. Untreated STIs are a preventable risk factor here, so getting tested and treated promptly makes a real difference in your risk profile.
Environmental Chemicals That Disrupt Your Ovaries
Endocrine-disrupting chemicals, particularly BPA (found in plastics, food can linings, and thermal receipt paper), have a surprisingly strong connection to ovarian cyst development. In animal studies, exposure to BPA at doses similar to typical human exposure levels dramatically disrupted ovarian function. Rats exposed to BPA during early development went on to show PCOS-like symptoms in adulthood: elevated testosterone, reduced progesterone, and ovarian cysts. A significant increase in ovarian cysts appeared at BPA doses as low as 1.0 microgram per kilogram of body weight per day.
Other endocrine disruptors, including phthalates (common in fragranced products and soft plastics), the fungicide vinclozolin, and dioxins, have all been shown to disrupt ovarian function in similar ways. Perhaps most striking, some of these effects appear to be transgenerational. When pregnant rats were exposed to a mixture of BPA and phthalates, their female offspring developed PCOS-like symptoms, and those symptoms persisted into the third generation of offspring who had no direct chemical exposure at all. While human studies are still catching up to the animal data, reducing your exposure to plastics, particularly when heating food, is a reasonable precaution.
Size, Torsion, and Rupture Risk
Cyst size is one of the clearest predictors of complications. Ovarian torsion, where the ovary twists on its blood supply, becomes a significant risk once a cyst reaches 5 cm or larger. The bigger it gets beyond that point, the higher the risk climbs. Functional cysts and corpus luteum cysts are among the most common types associated with torsion, especially during pregnancy, in women of reproductive age, and in those undergoing ovulation induction.
For simple, fluid-filled cysts under 3 cm, the risk of complications is low and no follow-up is typically needed. Cysts between 3 and 5 cm are usually monitored with a repeat evaluation in 4 to 6 months. Once a cyst exceeds 5 cm, or if it has complex features like internal walls, solid areas, or appears on both ovaries, surgical removal is more seriously considered.
Rupture risk also increases with size. A ruptured cyst can cause sudden, sharp pelvic pain, sometimes with internal bleeding. The warning signs that a cyst has worsened include sudden severe pain on one side of the pelvis, pain accompanied by fever (suggesting infection), dizziness or lightheadedness (suggesting internal bleeding), and pain with nausea or vomiting.
How Long Cysts Take to Resolve
Most functional ovarian cysts resolve on their own within a few weeks to a couple of months. During pregnancy, cysts that are present in the first trimester typically disappear by 14 to 16 weeks of gestation. If a cyst is still present after 16 weeks, it’s more likely to be a non-functional type that won’t go away on its own.
Outside of pregnancy, a cyst that persists beyond two to three menstrual cycles without shrinking warrants closer attention. The factors described above, hormonal imbalance, insulin resistance, infection, and ongoing chemical exposure, are the main reasons a cyst that should resolve instead sticks around or gets bigger. Addressing those underlying drivers, rather than just watching the cyst itself, is often the most effective approach to keeping things from getting worse.