[Extrauterine pregnancy: epidemiology and etiology].

The aim of the present study is to determine the epidemiological characteristics and etiological factors of ectopic pregnancy. The pool of women at risk is determined by different factors such as contraceptive practices, fertility rate, sterilization, gynecological and pelvic infection. Serological evidence of previous Chlamydia infection was much more common when ectopic pregnancy occurred in abnormal tubes than in normal tubes or compared to intrauterine pregnancies. The influence of endometriosis and ovarian cyst was limited to a very few cases. The analysis of contraceptive habits shows a much higher number of extrauterine pregnancies (45%) when the woman is using progestin-only pill than when she is on combined oral tablets (20%). This higher rate of ectopic gestation can be interpreted to suggest either that the POP might be less effective in preventing ectopic than intrauterine pregnancies or that the POP can delay ovum transport by inhibiting the motility of the fallopian tube.