We read with interest the case series reported by Barber et al, which highlights the risk of arteriovenous malformation (AVM) after conservative treatment of placenta percreta with uterine artery embolization (UAE) and adjunctive therapy. As these 3 reported cases occurred after adjunctive therapy (etoposide), the authors proposed the hypothesis that adjunctive therapy “may have less of an effect on newly formed vessels and their progression to form AVMs.” They also state that they report, to their knowledge, the first case of AVM following conservative treatment of placenta percreta. We would like to note that we have, in fact, previously published a case of AVM that occurred after a conservative treatment of placenta percreta without bladder invasion. Additional treatment included UAE but no antineoplastic agent (methotrexate or etoposide). Similar to the 3 cases reported by Barber et al, our AVM required a hysterectomy. This case was observed in a large national multicenter study including 167 cases of placenta accreta treated conservatively, where 18 cases were placenta percreta. Among these latter cases, additional uterine devascularization procedures were performed in 13 cases (8 UAEs and 5 vessel ligations). Although no definitive conclusion can be drawn from these limited data, and the pathophysiology of AVM following conservative treatment remains unknown, one can simply observe that the 2 common points of these 4 cases are: (1) the character percreta of the placental invasion; and (2) the additional treatment by UAE. Nevertheless, this does not exclude a possible role played by an antineoplastic agent in the pathophysiology of AVM. These 4 cases underline the need to continue to report maternal outcome following conservative treatment of placenta accreta/percreta, particularly because optimal treatment protocol of conservative treatment remains unknown.

As regards the optimal treatment for placenta percreta with adjacent pelvic structures, we could not agree more with the authors when they recommend performing conservative treatment. Concerning the optimal treatment for placenta accreta/increta, we agree with the authors that conservative treatment is associated with severe maternal morbidity. Nevertheless, this is also true regarding cesarean-hysterectomy for placenta accreta. Therefore, until a randomized controlled trial is performed, we believe that conservative treatment is an option in cases of placenta accreta/increta for patients who are properly counseled and motivated, in particular, for women who want the option of future pregnancy and agree to close follow-up monitoring.