This can also be done prenatally by testing fetal DNA obtained through either chorionic villus sampling or amniocentesis.

这可以在产前通过检测胎儿DNA完成，如绒毛膜绒毛取样或羊膜穿刺术。

Gases and nutrients move back and forth between the decidua basalis and the fetal veins, by diffusing through the tissue layer of the thin chorionic villi.

气体和营养物质通过在薄绒膜绒毛组织层之间扩散，在基蜕膜和胎儿静脉之间来回移动。

The fetal layer of the placenta on the other hand is called the chorion, which is a tissue that has fingerlike projections called chorionic villi which contain tiny fetal arterioles and venules.

胎盘的“胎儿层”也被称为绒毛膜；这是一种有绒毛膜绒毛这种手指状突起的组织，富含微小的胎儿动脉和静脉。