Natural Observation of Abortion of Heterotopic Cesarean Scar Pregnancy: A Case Report With Literature Review.

Heterotopic cesarean scar pregnancy (HCSP) is a rare condition in which an intrauterine pregnancy coexists with an ectopic pregnancy implanted in a cesarean scar. Due to its rarity, no standardized management has been established. Here, we report a 38-year-old Japanese woman diagnosed with HCSP, who experienced massive bleeding associated with spontaneous abortion (SA) of the cesarean scar pregnancy (CSP) at 8 weeks of gestation. The coexisting intrauterine pregnancy remained viable. As she desired pregnancy continuation, she was managed expectantly. At 335/7 weeks, she developed massive bleeding leading to hemorrhagic shock, necessitating emergency cesarean section. Bilateral uterine artery embolization was performed postoperatively to achieve hemostasis. Both the mother and her baby were discharged uneventfully. Although expectant management following SA of CSP in a dichorionic twin pregnancy may permit survival of the co-twin, pregnancy continuation carries a persistent risk of sudden-onset heavy bleeding. Active intervention for CSP in HCSP may improve perinatal outcomes.