Myomectomy scar ectopic pregnancy following a cryopreserved embryo transfer

Case A 40 year old woman with a history of a myomectomy visited the Department of Obstetrics and Gynecology, Niigata University Medical and Dental Hospital, Niigata, Japan, following 2 years of infertility. Magnetic resonance imaging detected an abnormal endometrial‐like pseudo‐cavity. A hysterosalpingography also revealed an abnormal accumulation of contrast medium at the myometrial scar site. A transvaginal ultrasound showed a thin myometrium at the lower uterine body. The patient conceived via in vitro fertilization under a luteal phase down‐regulation protocol (long protocol) for controlled ovarian stimulation, followed by a cryopreserved embryo transfer during her natural ovulation cycle. After the embryo transfer, the gestational sac was located at the subserosal site of the myomectomy scar. Outcome An emergent laparoscopic operation was performed and the embryo was removed successfully via laparoscopy under transvaginal ultrasonography. Conclusion A subserosal uterine pregnancy is a rare form of intramural pregnancy, which is a rare subtype of an ectopic pregnancy, which could occur at the myomectomy site, especially after an embryo transfer. It is believed that this rare ectopic pregnancy resulted from embryo implantation under the serosa through a micro‐sinus tract that was a site of suture failure of the myomectomy scar and was partially affected by the embryo transfer. Clinicians should consider the possibility of an ectopic pregnancy after uterine surgery, including a myomectomy.