Spironolactone can contribute to the development of functional ovarian cysts, though it is not a commonly listed side effect. The connection is indirect: spironolactone interferes with sex hormone production and can disrupt normal ovulation, which is the same mechanism behind most functional cysts in general. If you’re taking spironolactone for acne, hair loss, or blood pressure and have been told you have an ovarian cyst, the medication may be part of the picture.
How Spironolactone Affects Your Hormones
Spironolactone was originally designed as a blood pressure medication that blocks aldosterone, a hormone involved in fluid balance. But it doesn’t stop there. The drug also interferes with how your body produces and responds to sex hormones, which is why it’s widely prescribed off-label for hormonal acne and excess hair growth in women.
Spironolactone works as an antiandrogen, meaning it blocks the effects of testosterone and similar hormones at the tissue level. It also directly affects steroid hormone production in both the ovaries and adrenal glands. In women, this can shift the balance between estrogen and progesterone, the two hormones that coordinate your menstrual cycle. That hormonal disruption is what makes it effective against acne, but it’s also what opens the door to side effects like irregular periods, breakthrough bleeding, and changes in ovulation.
The Link Between Irregular Ovulation and Cysts
To understand why spironolactone could lead to ovarian cysts, it helps to know how cysts form in the first place. Every month, one of your ovaries develops a small fluid-filled sac called a follicle, which contains an egg. At mid-cycle, the follicle ruptures to release the egg. After ovulation, the empty follicle (now called the corpus luteum) produces progesterone for about two weeks and then dissolves.
Functional ovarian cysts happen when this process doesn’t go as planned. There are two common types:
- Follicular cysts form when the follicle grows but never ruptures to release the egg. Instead, it keeps filling with fluid and can grow larger than 20 mm.
- Corpus luteum cysts form when the follicle does release the egg but then seals back up and fills with fluid instead of shrinking away.
Both types are driven by the same underlying problem: a disruption in the hormonal signals that control ovulation. Since spironolactone directly alters gonadal steroid production and can elevate levels of gonadotropins (the pituitary hormones that tell the ovaries what to do), it can create exactly the kind of hormonal confusion that leads a follicle to stall or a corpus luteum to malfunction. In other words, the drug doesn’t grow cysts directly. It changes the hormonal environment in a way that makes cysts more likely to develop on their own.
Menstrual Irregularity as an Early Sign
Menstrual irregularity is one of the most commonly reported side effects of spironolactone in women. This can show up as spotting between periods, cycles that are shorter or longer than usual, or skipped periods altogether. These changes reflect the same underlying hormonal disruption that can lead to cyst formation.
If your periods have become unpredictable since starting spironolactone, that’s a signal your ovulation pattern has shifted. Not everyone who experiences irregular cycles will develop a cyst, but the two share a common cause. Many functional cysts produce no symptoms at all and resolve within one to three menstrual cycles without treatment. Others cause a dull ache on one side of the pelvis, bloating, or a feeling of pressure. Larger cysts, or those that rupture, can cause sharp, sudden pain.
How These Cysts Differ From PCOS Cysts
This is where things can get confusing. Many women who take spironolactone are already being treated for polycystic ovary syndrome (PCOS), a condition defined in part by the presence of multiple small cysts on the ovaries. If you have PCOS and develop a new or larger cyst while on spironolactone, it can be hard to tell whether the medication contributed or the cyst is just part of the underlying condition.
The distinction matters because the two types of cysts behave differently. PCOS-related cysts are typically numerous, small (under 10 mm), and represent follicles that started developing but stalled early. A functional cyst caused by disrupted ovulation is usually a single, larger fluid-filled sac, often greater than 20 mm. On an ultrasound, these look quite different. If your doctor identifies a single, larger cyst that wasn’t there before you started spironolactone, the medication’s hormonal effects are a reasonable explanation.
What You Can Expect
Most functional ovarian cysts are harmless and temporary. They typically resolve on their own within one to three cycles as hormone levels shift. Your doctor may recommend a follow-up ultrasound in six to eight weeks to confirm the cyst has shrunk or disappeared.
If you’re taking spironolactone alongside a combined birth control pill, your risk of functional cysts is generally lower. Hormonal contraceptives suppress ovulation more consistently, which reduces the chance of a follicle developing abnormally. Many dermatologists prescribe the two together for exactly this reason: the birth control pill stabilizes the menstrual cycle while spironolactone handles the androgen-related skin or hair issues. If you’re on spironolactone without hormonal contraception and you’re developing recurrent cysts or bothersome symptoms, adding a birth control pill is one of the most straightforward solutions.
Stopping spironolactone will also allow your hormone levels to return to baseline, and any functional cysts related to the medication should resolve as your normal ovulatory pattern returns. The timeline for this varies, but most women see their cycles regulate within one to two months of discontinuing the drug.
When a Cyst Needs Attention
A cyst that causes persistent pain, grows beyond 5 to 7 centimeters, or doesn’t shrink after a couple of cycles may need closer monitoring or intervention. Sudden, severe pelvic pain, especially with dizziness or nausea, can indicate a ruptured cyst or ovarian torsion (where the ovary twists on itself), both of which need urgent evaluation. These complications are uncommon but not unique to spironolactone. They can happen with any functional cyst, regardless of the cause.