Suspicion of an<unk>  is raised when the fetal anatomy can be easily felt, or the lie is abnormal, the cervix is displaced, or there is failed induction of labor. X-rays can be used to aid diagnosis. Sonography can demonstrate that the pregnancy is outside an empty uterus, there is reduced to no amniotic fluid between the placenta and the fetus, no uterine wall surrounding the fetus, fetal parts are close to the<unk>  wall, the fetus has an abnormal lie, the placenta looks abnormal and there is free fluid in the abdomen. MRI has also been used with success to diagnose<unk>  and plan for surgery. Elevated alpha-fetoprotein levels are another clue of the presence of an<unk> . Ultrasound A 23-week<unk>  on ultrasound showing a normal fetus and amniotic fluid. Most cases can be diagnosed by ultrasound. The diagnosis however may be missed with ultrasound depending on the operator's skill. Criteria To diagnose the rare primary<unk> , Studdiford's criteria need to be fulfilled: tubes and ovaries should be normal, there is no abnormal connection (fistula) between the uterus and the<unk>  cavity, and the pregnancy is related solely to the peritoneal surface without signs that there was a tubal pregnancy first. Studdiford's criteria were refined in 1968 by Friedrich and Rankin to include microscopic findings. Differential diagnosis Depending on gestational age the differential diagnoses for<unk>  include miscarriage, intrauterine fetal death, placental abruption, an acute abdomen with an intrauterine pregnancy and a fibroid uterus with an intrauterine pregnancy .
Abdominal pregnancy
Cervical pregnancy
Cryptic pregnancy
Heterotopic pregnancy
Malignant triton tumor
Postterm pregnancy
Recurrent miscarriage
Ectopic pregnancy