Introduction: Primary ovarian pregnancy is a rare ectopic gestation (<1% of ectopic pregnancies), usually presenting with first-trimester rupture. Progression to term with live birth is exceedingly rare and requires pathologic confirmation to exclude secondary implantation. Case Presentation: A 32-year-old multigravida underwent exploratory laparotomy for suspected ectopic pregnancy at term. A placenta-bearing mass involving the right ovary was identified, with a grossly normal ipsilateral fallopian tube. Right oophorectomy was performed, delivering a live female infant weighing 3,060 grams with Apgar scores of 8 and 9. Gross examination showed a large hemorrhagic placenta-like mass replacing the ovary with peripheral residual ovarian tissue. Histology revealed mature chorionic villi with syncytial knots, stromal fibrosis, calcifications, and abundant intervillous blood, directly implanted within ovarian stroma containing luteinized cells and corpus albicans remnants, with no tubal or endometrial tissue identified. Discussion: Advanced primary ovarian pregnancy is extremely rare and may mimic secondary abdominal or tubal implantation. Diagnosis relies on the Spiegelberg criteria, including an intact ipsilateral fallopian tube, ovarian location of the gestation, attachment through the ovarian ligament, and histologic demonstration of chorionic villi within ovarian stroma, confirming true ovarian implantation. Conclusion Clinical, gross, and microscopic findings fulfill the Spiegelberg criteria, confirming primary ovarian pregnancy. This rare term pregnancy highlights the crucial role of surgical pathology in establishing the definitive diagnosis and excluding secondary implantation.
Female ; Pregnancy ; Ovary ; Pregnancy, Ovarian