Analysis on risk factors and the expression of placental vascular endothelial growth factor in selective intrauterine growth restriction

Objective To evaluate the expression of placental vascular endothelial growth factor of twin pregnancies with selective intrauterine growth restriction (sIUGR) and its high risk factors.Methods There were 590 cases of twins delivered in Shenzhen People' s Hospital,including 42 cases of monochorionic diamnionic (MCDA) twins with sIUGR (case group) and 47 cases of dichorionic (DC) twins with sIUGR (control group A).Other 42 cases of MCDA twins without IUGR(control group B) were randomly selected.Placental weight and cord insertion were recorded at deliveries.The expression of vascular endothelial growth factor (VEGF) in human placenta was evaluated by immunohistochemistry.Results The incidence of perinatal death in the case group was higher than that in the control group (17.8％ vs 6.4％ vs 1.2％,P ＜ 0.01).The rate of velamentous cord insertion were 48.8％,10.6％ and 14.3％ in the case,control A and B groups,respectively (P ＜ 0.01).The mean placental weight of the big and small twins were (521 ± 149)g vs (258 ± 53)g in the case group.As for the sIUGR cases,the expression of VEGF in the placental tissue at the big babies' share were much higher than those of the small ones'.Conclusion The perinatal mortality was higher in MCDA sIUGR twins than those in DC twins or uncomplicated MC twins.The risk factors of MCDA sIUGR include unequal placental sharing,velamentous cord insertions and low expression of placenta VEGF. Key words: Monochorionic diamniotic twins;  Selective intrauterine growth restriction;  Outcome;  Risk factor