(HealthDay News) -- An ectopic pregnancy occurs when a fertilized egg grows outside the uterus, most commonly in the fallopian tube.

The growing fetus eventually will cause the fallopian tube to burst, which can lead to life-threatening bleeding that could require immediate surgery.

Half of women who develop an ectopic pregnancy have no known risk factors, the American College of Obstetricians and Gynecologists says.

Those risk factors that are known include:

• Previous ectopic pregnancy.
• Prior fallopian tube surgery.
• Previous pelvic or abdominal surgery.
• Certain sexually transmitted infections.
• Pelvic inflammatory disease.
• Endometriosis.
• Smoking.
• Being 35 years or older.
• History of infertility.
• Use of assisted reproductive technology, such as in vitro fertilization.

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According to the Mayo Clinic, seek emergency medical help if you have signs or symptoms of an ectopic pregnancy, including:

• Severe abdominal or pelvic pain during pregnancy
• Abnormal vaginal bleeding
• Extreme lightheadedness or fainting

Here are some question-and-answer threads from MyEndometriosisTeam:

• Was it difficult to get pregnant? Should I expect to struggle to become pregnant?

• I was just diagnosed with endo. I am 21 years old and my question is can I get pregnant naturally?

• I just found out I'm pregnant. So my question is, weather you had kids before or after endo, is the cramping normal?

Here are some conversations from MyEndometriosisTeam:

• "Hi is there anyone who has been through an ectopic pregnancy? I was going to post on the ectopic forum but the last person on there lost both her tubes so I know I should be grateful that that didn't happen. I am worried about getting another ectopic next time I try to get pregnant."

• "I was diagnosed with Endometriosis at 13. I'm 22 now. Since I have been diagnosed I have had 5 surgeries to clean it out and 2 to save my tubes from ectopic pregnancies. Sadly the second ectopic ruined my right tube and now I only have one."

• "Ready for January to hurry up and get here, so I can get off my BC and have the dye test US done to see if my left tube is still open. Unfortunately, if it has closed up again then that means another surgery because our doctor wants to remove that tube if it is closed as he doesn't want to open it up again in fear of an ectopic pregnancy due to scar tissue."

Have you experienced an ectopic pregnancy?
Share in the comments below or directly on MyEndometriosisTeam.