A case report is presented of a 24-year-old white woman gravida 1 para 0-0-1-0 who was admitted to the hospital with complaint of severe suprapubic pain 2 weeks after a normal menses. The patient had been inserted with a Dalkon shield 1-1/2 years prior to admission and it had been well tolerated. Laboratory results showed a positive urinary chorionic gonadotropin. A bilateral ovarian cystectomy revealed a right ovarian cyst containing chorionic villi dicidua and blood clots. The left ovarian cyst was consistent with a corpus luteum. The tubes were apparently normal. The IUD reduces uterine implantation by 99.5% but the incidence of expected ovarian pregnancy is unnaffected.