Story highlights A blood test can detect if a woman is "highly susceptible" to breast or ovarian cancer

Jolie reveals she carries a gene that increases her risk for cancer

Her mother died of ovarian cancer in 2007

Jolie is a U.N. special envoy and won an Oscar for "Girl, Interrupted"

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.

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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.

Photos: Life of Angelina Jolie Photos: Life of Angelina Jolie Actress Angelina Jolie has filed for divorce from husband Brad Pitt, a source familiar with the filing confirmed to CNN. Pitt and Jolie got married in 2014, but their relationship became the subject of speculation in 2004, when they co-starred in "Mr. & Mrs. Smith." At the time, Pitt was married to actress Jennifer Aniston. Despite recent recognition for her action movies and humanitarian works, Jolie has been in the spotlight since she was a child. Here's a look at her life. Hide Caption 1 of 28 Photos: Life of Angelina Jolie Jolie hugs her father, actor Jon Voight, in Los Angeles in 1980. Her brother, James, is at left. Hide Caption 2 of 28 Photos: Life of Angelina Jolie Jolie, then 15, poses for a photo in January 1991. Hide Caption 3 of 28 Photos: Life of Angelina Jolie Jolie and Voight are seen in an undated photo. Hide Caption 4 of 28 Photos: Life of Angelina Jolie Jolie attends an event in New York City, circa 1998. Hide Caption 5 of 28 Photos: Life of Angelina Jolie Jolie appears at the Golden Globe Awards in January 2000. She won best supporting actress for her role in the film "Girl, Interrupted." Hide Caption 6 of 28 Photos: Life of Angelina Jolie Jolie and her husband at the time, Billy Bob Thornton, appear at the premiere of her film "Gone in 60 Seconds" in June 2000. They divorced in 2003. Hide Caption 7 of 28 Photos: Life of Angelina Jolie Jolie and her mother, actress Marcheline Bertrand, are photographed at the premiere of Jolie's film "Original Sin" in July 2001. Bertrand died of ovarian cancer in January 2007. Hide Caption 8 of 28 Photos: Life of Angelina Jolie Jolie distributes balls to children at the Tham Hin refugee camp, on the Thailand-Myanmar border, in May 2002. She was a goodwill ambassador for the United Nations High Commissioner for Refugees before she became a special envoy for the agency in 2012. Hide Caption 9 of 28 Photos: Life of Angelina Jolie Jolie carries her son Maddox at the world premiere of "Shark Tale" in September 2004. Hide Caption 10 of 28 Photos: Life of Angelina Jolie Jolie appears on "The Tonight Show with Jay Leno" in March 2004. Hide Caption 11 of 28 Photos: Life of Angelina Jolie Jolie attends the German premiere of "Alexander" in December 2004. Hide Caption 12 of 28 Photos: Life of Angelina Jolie As part of her role as goodwill ambassador, Jolie speaks with Pakistani Prime Minister Shaukat Aziz in Islamabad, Pakistan, in May 2005. Hide Caption 13 of 28 Photos: Life of Angelina Jolie Producer Arnon Milchan centers Jolie and Pitt at the premiere of "Mr. & Mrs. Smith" in June 2005. Hide Caption 14 of 28 Photos: Life of Angelina Jolie Jolie and Pitt appear at the Cannes Film Festival in May 2008. Hide Caption 15 of 28 Photos: Life of Angelina Jolie Jolie greets fans at the Russian premiere of her film "Salt" in July 2010. Hide Caption 16 of 28 Photos: Life of Angelina Jolie Jolie walks with four of her children -- from left, Maddox, Zahara, Pax and Shiloh -- at Japan's Narita International Airport in July 2010. Jolie and Pitt are the parents of six children. Jolie gave birth to twins Vivienne and Knox in July 2008. Hide Caption 17 of 28 Photos: Life of Angelina Jolie Jolie appears at the Golden Globe Awards in January 2011. Hide Caption 18 of 28 Photos: Life of Angelina Jolie Jolie and Pitt appear at the Screen Actors Guild Awards in January 2012. Hide Caption 19 of 28 Photos: Life of Angelina Jolie Jolie meets Syrian refugees in Lebanon's Bekaa Valley in September 2012. Hide Caption 20 of 28 Photos: Life of Angelina Jolie Jolie appears at an April 2013 news conference in London about sexual violence against women in conflict. Hide Caption 21 of 28 Photos: Life of Angelina Jolie In May 2013, Jolie announced in a New York Times op-ed 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 and ovarian cancer. Here, in June 2013, she makes her first red carpet appearance since the surgery, attending the London premiere of Pitt's movie "World War Z." Hide Caption 22 of 28 Photos: Life of Angelina Jolie Jolie accepts the Jean Hersholt Humanitarian Award in November 2013, during the Academy of Motion Picture Arts and Sciences' Governors Awards ceremony. Hide Caption 23 of 28 Photos: Life of Angelina Jolie In the 2014 film "Maleficent," Jolie plays an evil sorceress who tells her side of the story. The movie opened at No. 1 and earned $69.4 million in its first weekend in U.S. theaters. Hide Caption 24 of 28 Photos: Life of Angelina Jolie In October 2014, Britain's Queen Elizabeth II made Jolie an honorary dame for her work to root out sexual violence in war zones. Hide Caption 25 of 28 Photos: Life of Angelina Jolie Angelina Jolie meets members of the Yazidi minority at a refugee camp in Khanke, Iraq, in January 2015. Hide Caption 26 of 28 Photos: Life of Angelina Jolie Jolie hugs her children Zahara, left, and Shiloh after winning an award during Nickelodeon's Kids' Choice Awards in March 2015. Jolie won Favorite Villain for her role in "Maleficent." Hide Caption 27 of 28 Photos: Life of Angelina Jolie Jolie greets refugees and migrants in the port of Piraeus, Greece, during a visit in March 2016. See Jolie before she was famous Hide Caption 28 of 28

"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.