Cause
A
functional ovarian cyst is caused by one or more
slight changes in the way the ovary produces or releases an egg. During the
normal monthly menstrual cycle, one of two types of functional cysts may
develop:
- A follicular, or simple, cyst occurs when the
small egg sac (follicle) on the ovary does not release an egg, and it
swells with fluid either inside the ovary or on its surface.
- A
luteal, or corpus luteum, cyst occurs when the remains of the egg follicle do
not dissolve and continue to swell with fluid. This is the most common type of
ovarian cyst.
The development of luteal cysts is also common during treatment
with
clomiphene citrate (such as Clomid or Serophene) for
infertility. These cysts go away after treatment is
completed, though this can take several months. They do not appear to endanger
pregnancy. For more information, see the topic
Fertility Problems.
Other ovarian growths
The development of functional cysts is directly related to
ovulation. However, there are other types of ovarian
cysts and growths caused by other conditions. An ovarian growth can be a
noncancerous (benign) cystic tumor or related to
endometriosis or cancer. In some cases, what seems to
be an ovarian mass is actually growing on nearby pelvic tissue. This is why
it's important for you to have regular pelvic exams and for your health
professional to carefully diagnose any cysts or growths felt on your ovaries.