What Is Endometriosis? Lena Dunham Had a Hysterectomy to Treat Painful Condition

Updated | Lena Dunham had surgery to remove her entire uterus due to endometriosis, a painful, chronic condition that can lead to infertility. This kind of surgery is considered a "last resort" treatment for the disease, according to the Mayo Clinic's website.

The actress, 31, announced she'd had the procedure done in an essay published in the March issue of Vogue. The Endometriosis Foundation of American published some quotes from the article on its website on Tuesday.

"I have retrograde bleeding, a.k.a. my period running in reverse so that my stomach is full of blood. My ovary has settled in on the muscles around the sacral nerves in my back that allow us to walk," Dunham wrote. "Let's please not even talk about my uterine lining. The only beautiful detail is that the organ—which is meant to be shaped like a light bulb—was shaped like a heart."

According to the excerpts, Dunham did not have her ovaries removed and she will soon "start exploring" if she may be able to use her own eggs in fertility treatment. She also wrote that "adoption is a thrilling truth I'll pursue with all my might."

Dunham previously wrote about her experience with endometriosis for Lenny Letter, the newsletter she co-founded, in 2015. She took a break before the fifth season of Girls began shooting in 2016 due to the condition.

Hey Beloved Pals,I just wanted to let you know that, while I am so excited for Girls to return on Feb 21, I won't be...

Posted by Lena Dunham on Monday, February 8, 2016

According to the National Institute of Child Health and Human Development, up to 5 million people in the United States may have endometriosis. Women are at a higher risk for endometriosis if their female relatives have the condition, if their period began before their 11th birthday, or if they have heavier or longer periods.

Some people manage the condition with pain medication. Hormones, including those found in birth control, can also help some people.

The symptoms of endometriosis happen when the endometrium—the tissue that lines the uterus—begins to grow beyond the organ and throughout a person's pelvis. This tissue can cause other organs in that part of the body, like the ovaries or fallopian tubes, to stick to each other. Dunham had surgery in April to correct these kinds of adhesions, Entertainment Weekly reported.

No one knows what causes a woman to develop endometriosis.

This article has been updated to include more details from Dunham's essay and about the symptoms of endometriosis.