An ovarian cyst is a fluid-filled sac that develops on an ovary. These sacs are usually harmless and often form as a normal part of the menstrual cycle. The most common types, known as functional cysts, develop when the process of releasing an egg does not proceed as expected. Hormonal contraceptives are frequently used to prevent the formation of these functional cysts by stopping the monthly ovulatory cycle. However, birth control does not guarantee that a cyst will never form, as different types of cysts and contraceptive methods affect ovarian activity in distinct ways.
The Role of Hormonal Contraception in Cyst Prevention
The intended function of combined hormonal contraceptives, such as the pill, patch, or ring, is to prevent pregnancy by suppressing ovulation. These methods contain both an estrogen and a progestin, which work together to regulate the body’s natural hormonal signals. They suppress the release of Gonadotropin-Releasing Hormone (GnRH) from the hypothalamus, which in turn prevents the pituitary gland from sending the necessary signals to the ovaries.
Specifically, the synthetic hormones prevent the surge of Luteinizing Hormone (LH) that normally triggers the release of an egg. By inhibiting this hormonal cascade, the combined contraceptives prevent the ovary from developing a dominant follicle that would eventually rupture to release an egg. Since functional cysts—follicular and corpus luteum cysts—arise directly from the normal mechanics of ovulation, suppressing this process significantly reduces their occurrence.
Types of Cysts That Persist or Develop While on Birth Control
While combined hormonal contraceptives are highly effective at preventing functional cysts, they do not offer complete protection against all types of ovarian growths. The cysts that can still occur fall into two main categories: those unrelated to the menstrual cycle and those that are a side effect of certain contraceptive types. This distinction is important because it dictates the nature of the cyst and the required medical attention.
The primary protection offered by hormonal birth control is against functional cysts, which are directly tied to ovulation. The body can still develop non-functional or pathological cysts, which are growths unrelated to the monthly cycle. These include dermoid cysts, which form from cells present since birth; endometriomas, which are cysts filled with old blood that occur in individuals with endometriosis; and cystadenomas, which grow from the cells on the outer surface of the ovary. These non-functional cysts develop independently of the hormonal fluctuations that combined contraceptives suppress. Therefore, a woman taking a combined pill, patch, or ring is still susceptible to developing them, and their presence is not a sign that the contraception has failed its purpose.
Another scenario where cysts can still develop is with the use of progestin-only contraceptive methods, such as the minipill or hormonal injections. Unlike combined methods, progestin-only options often do not consistently suppress ovulation in every user. This can lead to a phenomenon where a follicle begins to grow but does not successfully rupture to release the egg, forming a functional cyst.
These cysts are often referred to as Luteinized Unruptured Follicle (LUF) syndrome and are more common with progestin-only use than with combined methods. While they are generally benign, asymptomatic, and resolve spontaneously within a few cycles, this higher incidence of functional cysts is a recognized side effect for users of progestin-only contraceptives because the ovarian activity is not fully halted.
Recognizing Symptoms and When to Seek Medical Attention
Most ovarian cysts, even those that form while on birth control, are small and resolve on their own without causing symptoms. When symptoms do occur, they are often a dull ache or pressure in the lower abdomen, typically on one side. Other common signs include feelings of abdominal fullness or bloating, and sometimes pain during sexual intercourse.
While most cysts are harmless, it is important to recognize symptoms that suggest a complication and require immediate medical evaluation. The most serious complications are ovarian torsion, where the weight of a large cyst causes the ovary to twist, cutting off its blood supply, or a cyst rupture. Signs of a possible emergency include sudden, severe, and sharp pain in the pelvis or abdomen.
This severe pain, particularly when accompanied by other symptoms like nausea, vomiting, dizziness, or a fever, warrants an immediate visit to an emergency room. When a problematic cyst is suspected, the initial diagnostic step is usually a pelvic ultrasound to visualize the size, location, and characteristics of the growth. For most simple, fluid-filled cysts, the typical management is watchful waiting, which involves repeating the ultrasound in a few weeks to confirm that the cyst is shrinking while the user remains on their current birth control.