Peritoneal pregnancies are classified as primary and secondary. Primary imp
lantation on the peritoneum is extremely rare in extrauterine pregnancy and
is a potentially life-threatening variation of ectopic pregnancy within th
e peritoneal cavity, representing a grave risk to maternal health. Secondar
y abdominal pregnancies are by far the most common and result from tubal ab
ortion or rupture, or less often, after uterine rupture with subsequent imp
lantation within abdomen. Early diagnosis and appropriate surgical manageme
nt, regardless of stage of gestation, appear to be important in achieving g
ood results. We report a case of primary peritoneal pregnancy in a 28-year-
old woman, who had severe lower abdominal pain one day before laparotomy fo
r a preoperative diagnosis of ectopic pregnancy. The conceptus was implante
d on the left uterosacral ligament. A fresh embryo of approximately 8 weeks
' gestation was found in the conceptus.