Abstract: Objective To investigate the relationship between the level of erythropoietin producing hepatocyte receptor （Eph） A5 in sera and placenta tissues and pregnant outcomes in patients with placenta previa （PP）. Methods Ninety-eight patients with PP in the hospital were selected as observation group. Patients with complete, partial and marginal PP were included in groups A, B and C according to PP typing. Simultaneously, 40 healthy pregnant women were taken as the control. The prenatal blood samples and postpartum placenta tissues were collected in the observation groups and control . The level of Eph A5 in the sera and placental tissues of the all subjects were detected and followed up for occurrence of adverse pregnant outcomes. Results The level of Eph A5 in the sera and placentas of the observation groups was lower than that of the control （P<0.05）, much lower in groups A and B than group C （P<0.05）, but no significant difference was seen between group A and group B （P>0.05）. The incidence of adverse pregnant outcomes in maternal and perinatal children were 59.18% and 41.84%, respectively. The serum and placental Eph A5 level in the group of severe abnormal pregnant outcomes decreased compared with that of the mild ones （P<0.05）. No significant difference was noted of maternal serum Eph A5 among perinatal abnormal pregnancies （P>0.05）. Conclusion Eph A5 level in serum and placental tissues of patients with PP abnormally decreased, especially in patients with complete and partial placenta previa. The decreased level of serum Eph A5 is associated with maternal adverse pregnancies whereas Eph A5 in placental tissue is related to adverse fetal outcomes.

Key words: Placenta previa, Erythropoietin producing hepatocyte receptor A5, Pregnancy outcome, Placental tissue