Factors that can increase your risk of having an ectopic pregnancy include:¹

• A previous ectopic pregnancy.
• Past or present cigarette smoking, which increases your risk of having an ectopic pregnancy. The more you smoke, the higher the risk. Experts suspect that smoking affects fallopian tube function.^{1, 3}
• A history of pelvic inflammatory disease (PID), often caused by chlamydia or gonorrhea.
• Endometriosis, which can cause scar tissue in or around the fallopian tubes.
• Exposure to the chemical DES (diethylstilbestrol) before you were born.

Use of a copper intrauterine device (IUD) for birth control lowers your overall risk for ectopic pregnancy. This is because you are very unlikely to conceive with an IUD-only 1 to 6 per 1,000 progestin IUD users become pregnant per year. (However, these rare pregnancies are more likely than usual to be ectopic.)⁷

Medical treatments and procedures that can increase your risk of having an ectopic pregnancy include:

• Previous fallopian tube surgery to treat infertility or to reverse a tubal ligation.
• A tubal ligation failure. On the rare occasion that pregnancy happens after a sterilization surgery, there is a higher-than-usual risk that the pregnancy is ectopic.
• A progestin-only birth control failure (pills or implants).³
• Treatment with assisted reproductive technology (ART), such as in vitro fertilization (IVF).³ This may result from the flushing of the fertilized egg into a damaged fallopian tube after it is transferred to the uterus.
• Infection after any kind of surgery done on the uterus or fallopian tubes. This can lead to scar tissue.⁸

Ectopic pregnancy has been linked to the use of medicine used to make the ovary release multiple eggs (superovulation). Experts do not yet know whether this is because many women using it already have fallopian tube damage or because of the medicine itself.¹

If you become pregnant and are at high risk for ectopic pregnancy, you will be closely monitored. Health professionals do not always agree about which risk factors are serious enough to watch closely. However, research suggests that risk is serious enough if you have had a tubal surgery or an ectopic pregnancy before, had DES exposure before birth, have known fallopian tube problems, or have a pregnancy with an intrauterine device (IUD) in place.¹