Comparison of Extravillous Intermediate Trophoblast Invasion Depth and Distribution Pattern Between Placenta Accreta and Non-Accreta.

BACKGROUND Placenta accreta spectrum (PAS) is a complex obstetric complication that poses a major risk for life-threatening hemorrhage. The pathogenesis of PAS is known to be related to placentogenesis, trophoblastic cells invasion, and previous obstetrical procedures that cause uterine wall defects. However, the precise mechanism of this disease has not been fully explained. This study aimed to evaluate the differences in maximum depth of invasion and distribution pattern of implantation site intermediate trophoblasts between PAS and non-accreta cases. MATERIAL AND METHODS This was an observational, analytic, cross-sectional study that utilized paraffin block specimen of peripartum hysterectomy performed in Hasan Sadikin General Hospital Bandung from 2018 to 2020. Sixty-four samples were obtained, then classified as PAS and non-accreta (normal placenta). Implantation site-intermediate trophoblasts were identified using CD-146 staining. Maximum invasion depth of intermediate trophoblasts was measured in micrometers, while the distribution pattern was assessed and classified into 2 groups: confluent and scattered. RESULTS We found that the maximum invasion depth of the intermediate trophoblasts was significantly higher in the PAS group compared to that of the non-accreta group (2453.52±1172.122 µm vs 1613.59±822.588 µm, P=0.009). The confluent distribution pattern was significantly more common in the PAS group compared to that of the non-accreta group (87.2% vs 17.6%, P=0.0001). CONCLUSIONS The findings of our study suggested that implantation site intermediate trophoblasts play a role in the pathophysiology of placenta accreta. Further studies are needed to determine factors that affect trophoblast invasion leading to placenta accreta spectrum.