Background: To study placental bed biopsy changes in placenta previa and normally implanted placenta.
Subject and method: Fifty placental bed biopsies from 50 patients with placenta previa and 50 placental bed biopsies from normally implanted placenta were taken at cesarean section. Placental bed biopsy was stained with hematoxyline and eosin for histological examination. Both the groups were compared for trophoblastic invasion and vascular changes of placental bed spiral arteries. Statistical analysis was done by Chi-square test.
Results: Placenta bed biopsy was representative in 42/50 (84%) biopsy samples of the study group (placenta previa) and 35/50 (70%) of the control group (normally located placenta). Trophoblastic giant cell migration into decidua was present in 100% of representative samples of both the groups while migration into myometrium was seen in 66.67% and 51.14% of samples of study and control group. Average number of trophoblastic giant cells per sample was significantly higher in placenta previa (decidua 41.3%, myometrium 52%) than the control group (decidua 17.4%; myometrium 14.5%). Trophoblastic giant cell infiltration into myometrial spiral arterioles was higher in placenta previa (81.83 cells per vessel). Percentage of myometrial spiral arterioles showing physiological changes was significantly higher in the study group (50.39%) compared to the control group (21.14%). Incidence of inflammatory cell infiltration was higher in the study group (42.86%). Hemorrhage into decidua and myometrium were seen in biopsy samples of the placenta previa.
Conclusion: Placenta previa is associated with significantly higher trophoblastic giant cell infiltration and physiological changes of the myometrial spiral arterioles.