Endometriosis is caused by abnormal growth of the uterine lining (endometrial tissue) outside of the uterus.

Endometrial tissue responds to the hormonal changes of ovulation and sheds out during your period. With endometriosis, the tissue outside of the uterus has nowhere to shed. This can cause pain. The condition is estrogen-dependent, so symptoms diminish as estrogen levels decrease. This occurs during pregnancy and after menopause.

Some women with endometriosis experience few symptoms. Others feel extreme pelvic pain.

Other symptoms of endometriosis include:

  • severe menstrual cramping
  • heavy menstrual bleeding, or spotting between periods
  • pain during intercourse, urination, or with bowel movements
  • depression
  • fatigue
  • nausea

Endometriosis affects 1 in 10 women of reproductive age. Having a family history of endometriosis may be a risk factor for getting the disorder, although experts don’t completely understand the exact cause or causes. Endometriosis often clusters in immediate family circles, but it can also be found in first or second cousins.

Read on to learn more about the research into endometriosis and genetics.

The exact cause of endometriosis isn’t known, although heredity appears to be a large part of the puzzle. Environmental factors may also play a role.

The condition often affects members of the same nuclear family, such as sisters, mothers, and grandmothers. Women with cousins who have the condition are also at an increased risk. Endometriosis can be inherited via the maternal or paternal family line.

Researchers are currently studying theories about its causes and risk factors. Some possible causes of endometriosis include:

  • Complications from surgical scarring. This can occur if endometrial cells attach to scar tissue during a surgical procedure, such as a cesarean delivery. Learn more about the symptoms of endometriosis after this type of surgery.
  • Retrograde menstruation. The backward flow of menstrual blood into the pelvic cavity may displace endometrial cells outside of the uterus.
  • Immune system disorder. The body may not recognize, and eliminate, endometrial cells outside of the uterus.
  • Cell transformation. Endometriosis can occur anywhere in the body. This may be caused by internal changes in cells outside of the uterus, which turns them into endometrial cells.
  • Cell transportation. Endometrial cells may travel through the blood system, or lymphatic system, to other parts of the body, where they adhere to other organs.

Endometriosis is thought to have a genetic predisposition, which may make some women more likely to get it than others. Multiple studies have examined familial patterns and endometriosis.

An older study, from 1999, analyzed the prevalence of endometriosis in 144 women, using laparoscopy as a diagnostic tool. An increased incidence of endometriosis was found to exist in first-, second-, and third-degree relatives, including sisters, mothers, aunts, and cousins.

A large, population-based study from 2002 of the entire nation of Iceland, using a genealogy database going back 11 centuries, found a raised risk for endometriosis among both close and distant relatives. The study looked at sisters and cousins of women diagnosed with endometriosis from 1981 to 1993. Sisters were found to have a 5.20 percent greater risk of getting the disease than those without a sibling with endometriosis. First cousins, on either the mother’s or father’s side, were found to have a 1.56 percent greater risk than those without a family history of the disease.

An analysis of multiple studies, reported in Clinical Obstetrics and Gynecology, determined that endometriosis clusters in families. Researchers speculated that multiple genes, as well as environmental factors, may play a role.

Your doctor will determine your treatment based on the severity of your symptoms and your goals, such as pregnancy. It’s important to know that women with endometriosis can often get pregnant.

Medications are often prescribed to treat endometriosis symptoms, such as pain. Hormonal medications — such as contraceptives — may help to ease symptoms by reducing estrogen levels or by halting menstruation.

Removing endometriosis can be done surgically, although the tissue often returns over time. Surgical procedures include minimally invasive laparoscopy and traditional abdominal surgery. Traditional surgery may be the better option if your endometriosis is widespread or severe.

In very severe cases, your doctor may recommend a total hysterectomy. This procedure removes the uterus, cervix, and both ovaries. It also eliminates your ability to become pregnant. If your doctor recommends a total hysterectomy, discuss egg freezing and other fertility-preservation options first. You may also want to get a second opinion before proceeding. Check out Healthline’s 2017 state of fertility report to learn more about fertility attitudes and options.

In vitro fertilization, an assisted reproductive technology procedure, doesn’t eliminate endometriosis, but it may make it possible for conception to occur.

What you can do

Endometriosis is a progressive disease, which can begin at any time after puberty. If endometriosis runs in your family, you may feel there’s little you can do. But women who have family members with endometriosis should seek medical support if they experience any symptoms, such as severe menstrual cramping. This can help reduce the immediate impact, easing symptoms such as pain and depression. It may also help reduce the chances of experiencing infertility later on.

Lifestyle changes can also help. Having a low body mass index, or being underweight, may increase the chances of getting endometriosis, so you should avoid this if you have a familial history. Drinking alcohol to excess may also increase your risk and should be avoided.

According to one study, eating a healthy diet which includes good fats and avoids trans fats may help reduce your risk of getting the disease.

Endometriosis doesn’t appear to have one definitive cause, but it may result from the interplay of your genetics and environment. Having a family history does increase your risk in some cases. Being proactive and seeking an early diagnosis can help increase your quality of life. It can also provide an opportunity to plan for pregnancy, if that’s your goal.

Whether you have a family history of endometriosis or not, talk to your doctor if you have symptoms or concerns. If you’re living with pain, seeking out pain relief will help.