The utility of serum markers in the conservative management of placenta accreta spectrum ( PAS ) by leaving the placenta in situ in women with high‐grade PAS

OBJECTIVE: To investigate the association between serum markers and successful conservative management of patients with placenta accreta spectrum (PAS). METHODS: This was a retrospective case-control study where patients with high-grade PAS between 2011 and 2025 undergoing conservative leaving the placenta in situ were included. The management followed the Frankfurt PAS Procedure where the placenta was left in situ after cesarean section (CS) followed by uterine artery embolization and two-step surgery. Regular laboratory investigations included the assessment of serum markers including beta human chorionic gonadotropin (β-hCG), serum placental growth factor (PlGF), progesterone, and pregnancy-associated plasma protein A (PAPP-A). Mixed effects models with random intercept were utilized to assess the association between the marker levels and uterine preservation over follow-up time. RESULTS: The study included 24 women, seven of which with successful uterine preservation had lower β-hCG, PlGF and progesterone with medians of 1469 (282.2, 5532), 117 (27.2, 258), and 24.5 (4.2, 66) compared to the 17 needing hysterectomy with medians of 9041 (3563, 16 824), 227.2 (129, 368), and 60 (47, 83), respectively, but no difference in PAPP-A levels. The mixed effects models showed a decline for β-hCG, PAPP-A, progesterone over time (P < 0.001), but not for PlGF. The rate of β-hCG drop was higher for patients with preserved uterus especially within the first two weeks of follow-up with a coefficient of 311 mIU/mL per day. CONCLUSION: β-hCG, PlGF and progesterone levels successively decrease after conservative PAS management, and there is a negative association between successful uterine retention and serum β-hCG levels. The optimal window for performing a two-step surgery might be 2-3 weeks post CS.