[Role of echography in the diagnosis of extra-uterine pregnancy. Value of the double sac sign].

Ultrasound images showing normal intrauterine pregnancy with embryo practically excludes the presence of an extrauterine pregnancy (E.U.P.). The efficacy of the double sac sign in establishing, almost definitely, a normally implanted pregnancy makes it important for this sign to be recognized. In other cases (absence of double sac sign, empty uterus with or without an associated fluid mass in the cul de sac) the risk of an E.U.P. varies and more aggressive exploratory methods are necessary to confirm the diagnosis.