The efficacy of the placental biopsy

OBJECTIVE: Our purpose was to determine the sensitivity and specificity of pathologic diagnoses made from a placental biopsy specimen compared with diagnoses made from a complete placental examination. STUDY DESIGN: Biopsy was performed on 200 singleton placentas with a 16-gauge Rutner biopsy needle shortly after delivery. The biopsy specimens and placentas were evaluated by standard placental pathologic criteria. RESULTS: The presence of villous edema on the biopsy specimen led to the diagnosis of placental villous edema with a sensitivity of 51% and specificity of 86%, yielding a positive predictive value of 0.97, The sensitivity of the biopsy diagnosis of "increased syncytial knots" was 86%, whereas the specificity was 82%, yielding a positive predictive value of 0.90. CONCLUSIONS: Because a placental biopsy specimen after delivery is reasonably sensitive for diagnosing villous abnormalities that reflect acute and chronic stresses to the placenta, it may be useful to develop a placental biopsy that can be performed safely during pregnancy. Such a biopsy could be the basis for the rational treatment of some diseases of pregnancy. (AM J OBSTET GYNECOL 1995; 173:1084-8.)