(CNN) -- Actress Angelina Jolie announced in a New York Times op-ed article on Tuesday that she underwent a preventive double mastectomy after learning that she carries a mutation of the BRCA1 gene, which sharply increases her risk of developing breast cancer and ovarian cancer.
"My doctors estimated that I had an 87 percent risk of breast cancer and a 50 percent risk of ovarian cancer, although the risk is different in the case of each woman," Jolie wrote. "Once I knew that this was my reality, I decided to be proactive and to minimize the risk as much I could. I made a decision to have a preventive double mastectomy."
Jolie's mother, actress and producer Marcheline Bertrand, died of ovarian cancer in 2007 at the age of 56. Jolie is 37 years old.
In the Times op-ed, titled "My Medical Choice," Jolie said she finished three months of medical procedures at the Pink Lotus Breast Center in California on April 27 that included the mastectomies and reconstruction.
A mastectomy is an operation that removes all or part of the breast.
She wrote that her experience involved a three-step process. On February 2, the actress had a procedure that increases the chance that the nipple can be saved. Two weeks later, she had major surgery where the breast tissue was removed and temporary fillers were put in place. Nine weeks later, she described undergoing "reconstruction of the breasts with an implant."
"There have been many advances in this procedure in the last few years," she said, "and the results can be beautiful."
"I wanted to write this to tell other women that the decision to have a mastectomy was not easy. But it is one I am very happy that I made," Jolie wrote. "My chances of developing breast cancer have dropped from 87 percent to under 5 percent."
BRCA stands for breast cancer susceptibility genes, a class of genes known as tumor suppressors, according to the National Cancer Institute.
Mutations of the BRCA1 and BRCA2 genes have been linked to hereditary breast and ovarian cancer. A blood test can determine if a woman is "highly susceptible" to the cancers.
Jolie may be best known for title role in the "Lara Croft" series of films, but she also won an Academy Award for best supporting actress in "Girl, Interrupted." She also received a Golden Globe Award and SAG Award for the same role.
Jolie serves as a special envoy for the United Nations High Commissioner for Refugees and has visited refugee camps around the world.
The actress has been in a relationship with actor Brad Pitt since the mid-2000s, and they are engaged. The couple has three biological and three adopted children.
In telling her story, Jolie acknowledged that surgery might not be the right choice for every woman.
"For any woman reading this, I hope it helps you to know you have options," Jolie wrote. "I want to encourage every woman, especially if you have a family history of breast or ovarian cancer, to seek out the information and medical experts who can help you through this aspect of your life, and to make your own informed choices."
But for Jolie, the decision ultimately came down to her kids.
"I can tell my children that they don't need to fear they will lose me to breast cancer," she said.