Blood in the maternal circulation is delivered via open ended arterioles to the intervillous space of the chorionic plate, where it bathes the chorionic villi that carry umbilical capillary beds, thereby allowing gas exchange to occur between the maternal and fetal circulation.
22.
The interface between fetal and maternal components of the placenta is rather distinct : the decidua basalis ( maternal ) is separated from the chorionic villi by a cytotrophoblastic shell that is derived from fetal tissue ( the trophoblast ) and is several cells thick.
23.
The interface is at the chorion ( on the fetal side ) which forms chorionic villi that project into the decidua ( mother's side ); this is interface where nutrients and blood gases are exchanged in the placenta . talk ) 02 : 56, 7 April 2007 ( UTC)
24.
Maternal tissue only plays a role in support ( the maternal decidua basalis is the supportive structure to which the fetal placental component attaches ) and in placental circulation ( the spiral arteries of the maternal endometrium penetrate the developing chorionic villi and bathe the fetal tissue in maternal blood ).
25.
Non-invasive prenatal diagnosis ( NIPD ) and Non-invasive prenatal testing ( NIPT ) have been implemented in the UK and parts of the US; it has clear benefits above the standard tests of chorionic villi sample ( CVS ), amniocentesis, and other diseases which have procedure-related miscarriage risks of about 1 in 100 pregnancies and 1 in 200 pregnancies, respectively.
