Unexpected placenta accreta spectrum after the use of assisted reproductive technology in women with adenomyomectomy.

Placenta accreta spectrum (PAS) is a rare complication that can lead to life-threatening postpartum hemorrhage. PAS can sometimes occur unexpectedly, without placenta previa;such cases can lead to higher maternal mortality and morbidity than expected cases. Here, the authors report a case of unexpected PAS caused by assisted reproductive technology (ART) in a woman with adenomyosis. The patient was a 37-year-old Japanese primipara woman who presented to our hospital at 11 weeks gestation, later returning to her parents' house to give birth. The woman had adenomyosis and underwent adenomyomectomy, which was followed by an ART pregnancy. The patient was admitted to our hospital because of a life-threatening preterm birth, with a short cervix and no evidence of placenta previa. Despite strict perinatal management, preterm rupture of the membrane (PROM) occurred. During laparotomy, the small intestine, rectum, and both right and left ovaries were clumped together and severely adhered to the surface of the uterus. After delivery, manual partial removal of the placenta was performed, resulting in heavy bleeding from the implantation site, which was diagnosed as an unexpected PAS. Following several uterine compression efforts, we successfully preserved the uterus.