Can placental pathology explain second-trimester pregnancy loss and subsequent pregnancy outcomes?

Objective: This study sought to determine whether specific placental pathology may provide further insight into the mechanisms of second-trimester pregnancy loss, particularly in cases without inflammation. Study Design: A blinded pathologist examined placentas from 90 patients with spontaneous second-trimester pregnancy loss and 17 controls who presented for induction of labor for fetal indications. Inflammation was staged and evidence of other vascular pathology recorded. Significant associations were determined by χ² analysis and Fisher's exact test. A secondary analysis examined losses without inflammation. Twelve patients with a subsequent pregnancy were also evaluated. Results: Acute inflammation was more prevalent in cases than controls (P < .001). Sixty-seven percent of all cases and none of the controls showed a stage 2-3 inflammatory response. Histologic abruption was also more prevalent in cases than controls (P = .05). Conclusion: Second-trimester pregnancy loss is strongly associated with placental inflammation. Histologic abruption is likely another etiology. Future research should focus on subsequent pregnancy outcomes in these women based on initial placental pathology to help determine etiology and recurrence risk.