Up to an estimated 20 in every 1,000 pregnancies are ectopic. Various factors are associated with ectopic pregnancy, including:

  • Previous ectopic pregnancy. If you've had one ectopic pregnancy, you're more likely to have another.
  • Inflammation or infection. Inflammation of the fallopian tube (salpingitis) or an infection of the uterus, fallopian tubes or ovaries (pelvic inflammatory disease) increases the risk of ectopic pregnancy. Often, these infections are caused by gonorrhea or chlamydia.
  • Fertility issues. Some research suggests an association between difficulties with fertility — as well as use of fertility drugs — and ectopic pregnancy.
  • Structural concerns. An ectopic pregnancy is more likely if you have an unusually shaped fallopian tube or the fallopian tube was damaged, possibly during surgery. Even surgery to reconstruct the fallopian tube can increase the risk of ectopic pregnancy.
  • Contraceptive choice. With proper use, pregnancy when using an intrauterine device (IUD) is rare. If pregnancy occurs, however, it's more likely to be ectopic. The same goes for pregnancy after tubal ligation — a permanent method of birth control commonly known as "having your tubes tied." Although pregnancy after tubal ligation is rare, if it happens it's more likely to be ectopic.
Feb. 09, 2012