The incidence of placenta accreta spectrum (PAS) is rising, and focal forms often remain undetected until delivery, when severe postpartum hemorrhage may rapidly occur. Conservative management is desirable for women wishing to preserve fertility; however, emergency conditions often limit the applicability of established surgical techniques. We report two cases of unexpected focal placenta accreta diagnosed intraoperatively in pregnancies achieved through in vitro fertilization and oocyte donation. Both women underwent cesarean delivery and developed massive hemorrhage. Standard measures failed, prompting surgical excision of the invaded myometrial area using the HARMONIC FOCUS+ Long Shears, which enable simultaneous cutting and coagulation with minimal thermal spread. Both patients required transfusions and short ICU admission but recovered fully, with no retained products on postoperative ultrasound. These cases suggest that ultrasonic energy may represent a valuable conservative option for rapid bleeding control and uterine preservation in emergency settings where prenatal diagnosis is lacking.