The Effect of Placenta Previa on Fetal Weight and Feto-maternal Blood Flow

Placenta previa is a placenta that implants at lower uterine segment, it occurs in about 0.3-0.5% of pregnancies at term. It is a significant risk for development of maternal morbidity, as well as maternal mortality secondary to maternal hemorrhage . Also, this abnormal placenta has a negative concern about fetal well being due to prematurity and perinatal mortality, in addition to its undesirable effect on fetal growth. Several factors may be behind of the effect of placenta previa on fetal growth. Firstly, the blood supply to the lower uterine segment is less than at the upper segment apparently resulting in less feto-placental blood perfusion . Secondly, recurrent bleeding attacks from placental previa may affect fetal oxygenation and fetal growth.

In spite of above evidences; many studies in literature denied the relation between placenta previa and fetal growth and concluded that the association between low birth weight and placenta previa is mainly due to preterm delivery and to a lesser extent with fetal growth restriction. However; the major drawback of all these studies is lacking of reporting the effect of placenta previa of feto-maternal blood flow representing in studying of Doppler blood flow in both uterine and umbilical artery in those patients. The uterine artery blood flow is usually affected by the presence of placenta previa and placenta accreta which reflected on feto-placental blood flow. So the uterine artery Doppler velocimetry is a useful tool for predicting placenta accreta .

So in the light of above evidences; we aimed, in the current study, not only to investigate the effect on placenta previa on fetal weight but also to walk around the effect of placenta previa on the uterine and umbilical arteries blood flow in trial to explore this conflicting issue. To our knowledge, no previous trial had studied this interesting subject before.