risk factors

Last reviewed 09/2023

Risk factors are recognized only in 25-50% of patients who receive a diagnosis of an ectopic pregnancy (1).

Predisposing factors for an ectopic pregnancy include:

  • previous tubal surgery
  • previous ectopic pregnancy
  • previous induced abortion
  • pelvic inflammatory disease (2)
  • intrauterine contraceptive devices - although conception rarely occurs with an intrauterine device in place, 25 to 50% of such pregnancies are thought to be ectopic (3)
  • tubal ligation
  • assisted reproductive techniques – in women who underwent in vitro fertilisation:
    • the risk of ectopic pregnancy was increased even in women with normal fallopian tubes
    • the risk of heterotopic pregnancy is also increased to 1 case per 100 women  from 1 case per 4000 women in the general population (3)
  • history of sub-fertility - probably because it identifies a group of women with tubal problems (due to altered tubal integrity or function) (3)
  • progestogen only, or mini, pill
  • diethylstilboestrol exposure
  • non-caucasian race
  • hormonal factors:
    • induction of ovulation
    • delayed ovulation
    • ovum transmigration
  • minor risk factors include:
    • history of cigarette smoking
    • women over 35 years
    • multiple sexual partners during the lifetime (3)

The risk of ectopic pregnancy increases with maternal age (2).

Notes:

  • endometriosis and ectopic pregnancy
    • a retrospective large population-based study seems to question any role of endometriosis in the aetiology of ectopic pregnancy (2)
    • the study authors do however note that
      • "..mild endometriosis could have been missed during emergency surgery for a bleeding ectopic pregnancy unless it was specifically searched for. Moreover, as most operations were performed by laparotomy, it is likely that mild endometriosis was underdiagnosed due to hemoperitoneum.."

Reference:

Related pages:

intrauterine contraceptive device

pelvic inflammatory disease

mini pill

ectopic pregnancy (risk with respect to diff contraception)