The Placenta and the umbilical Cord

The Placenta, which attaches the baby to the mother while in the uterus, is rich in oxygen and nutrients. After delivering her baby via the birth canal, the mother will have a second contraction to push out the placenta.

For mothers going through a Caesarean section, the obstetrician will either remove the placenta manually or wait for about five minutes for it to detach itself naturally.

The umbilical cord-the lifeline that transfers nutrients from mother to baby during pregnancy-is rich in haematopoietic (Blood-forming) stem cells.

These cells are able to develop into various specialised cells, eg, red r white blood cells, platelets, muscles, etc. If not obtained from umbilical cord blood, stem cells can also be harvested from bone marrow.

Extracting stem cells

After the baby is born, the umbilical cord is clamped on both ends and cut. The clamp is removed at one end and a tube is passed through the vein in the umbilical cord to collect blood. The placenta also contains blood vessels, from which blood and cells can be extracted. The amount of cord blood collected from a C-section is usually less than from a vaginal birth.

In most cord blood banks, the volume of blood collected is reduced through the removal of plasma. This decreases the amount of nitrogen required for preservation. Plasma is separated from other components in cord blood via a process known as centrifugation. The components are separated by their weight –red blood cells at the bottom, plasma on the top and a buffy coat in between. Most of the time, the buffy coat is stored.  

Preserving stem cells

Stem cells are frozen cryogenically, meaning they are stored in storage tanks containing liquid nitrogen. To do this, laboratory technicians need to eliminate all water content to prevent the formation of ice crystals. Ice crystals will rupture cell membranes, thus destroying the stem cells.