In some cases, the presence of a cyst necessitates an ovary removal, also known as a Oophorectomy.  Doctors do try to avoid this, as there is evidence that having your ovaries removed can cause problems later in life.  However, there sometimes is no other option to successfully treat a large or recurrent ovarian cyst.
When it is removed, doctors attempt to only remove the ovary affected by the cyst.  This way, you still have an ovary producing hormones.  However, if cancer is suspected, both ovaries are removed, along with the fallopian tubes and the uterus.

Who Ovary Removal Affects

Generally, ovary removal is avoided.  However, if the cyst is large, causes ovarian torsion, or is suspected to be cancerous, the ovary is generally removed along with the cyst.
When you go in for a cystectomy, the doctor may tell you they will try to leave the ovary.  However, you should know there is a chance they will have to remove it once they are operating.  If the doctor suspects cancer, the uterus and fallopian tubes may be removed as well.

Risks of Ovary Removal

While the surgery itself is a relatively safe procedure, there are some risks involved.  First, there is always the danger of bleeding, infection, and damage to nearby organs.  There is also a small chance that some ovarian cells could be left behind, continuing to form cysts and cause pain even after the ovary is removed.
After an ovary is removed, a woman is at risk for premature menopause.  This can cause symptoms such as hot flashes, depression or anxiety, heart disease, memory problems, decreased sex drive, osteoporosis, and even premature death.  Some of these side effects may be avoided by taking hormone replacement therapy.  However, hormone replacement can carry risks of its own.

How Ovary Removal is Performed

Generally, ovaries are removed during laparascopy.  However, if you have a large, solid cyst greater than 2 ½ inches in diameter, traditional surgery will need to be performed.  Also, a laparascopy can change into traditional surgery during the procedure if cancer is suspected.