Moreover, CD31 positive expression in the abortion group was significantly lower than that in the control group (P < 0.01), while CD31 expression in the abortion+shmiR-381-3p group was significantly higher than that in the abortion group (P < 0.05) (Fig. 5B), suggesting that miR-381-3p knockdown may promote angiogenesis in the placenta to improve ischemic/anoxic state of the placenta in the abortion mice. The gene discussed is PECAM1; the disease is abortion.