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Pregnant patients are more likely than ever to ask about stem cells and umbilical cord blood banking. In this article, an expert provides an update on the pros and cons of cord blood banking, and the controversy over private versus public banks, to help you counsel appropriately.
Not so long ago, ob/gyns didn't think twice about tossing out the leftover blood in the umbilical cord and placenta (UCB) after delivery. Our perspective changed, however, with the discovery that cord blood is a valuable source of hematopoietic stem cells. That, in turn, led Gluckman to undertake the first transplant with UCB in a sibling-a 6-year-old boy with Fanconi's anemia in 1988.1 Since then, more than 6,000 UCB transplants have been performed for many different (non-autologous only) indications.
Pros and cons of cord blood as a source of hematopoietic stem cells
Stem cells from cord blood offer several clear advantages over bone marrow donation or collecting peripheral stem cells from an adult donor. Bone marrow donation entails a computerized search to locate a potential donor through the National Marrow Donor Program. The candidate must then undergo additional testing and bone marrow harvest, with its attendant risks. In contrast, pretested UCB units are readily available through a computerized search. With this approach, a unit becomes available in about one quarter of the time (written communication from Christina Grier, National Donor Program, September 2005).
A major drawback of UCB is that the total cell dose is roughly 10% of a typical adult bone marrow donor unit, which limits transplants to children and small adults.3 If in vitro expansion of the units and use of combined units prove promising, adults may, in the future, be eligible for the transplants.
How cord blood is collected
As an obstetrician/gynecologist, you'll want to educate yourself about the pros and cons of the types of UCB banks so you can present balanced information to pregnant patients, preferably during the third trimester.4 If a woman chooses to donate to a public bank, make every effort to obtain her consent before the onset of labor. But when that's not possible, obtain a mini-consent during labor, followed by a full consent postpartum. You can access the list of public banks that are members of the National Bone Marrow Donor Program (NMDP) at http:// http://www.marrow.org/cgi-bin/NETWORK/nmdp_cord_blood_banks.pl. The link for non-NMDP blood banks is http:// http://www.marrow.org/NMDP/non_nmdp_cord_blood_banks.html.
Patients must undergo extensive screening before their UCB can be accepted into a public bank. Screening involves a thorough family history of the donor aimed at identifying hematologic and immune abnormalities and various malignancies and testing the infant donor or the cord blood to exclude homozygous hemoglobinopathy. The patient's history also is reviewed to exclude overseas travel to specific countries, exposure to live viral vaccines within the previous 3 months, use of illicit drugs, and high-risk sexual behavior. At the time of admission to labor and delivery or immediately postpartum, infectious serologies for viral and bacterial disease are drawn, as is required by the Food and Drug Administration (FDA) for any blood donation. Included in the testing are hepatitis B and C, HIV 1 and 2, HTLV 1 and 2, West Nile virus, and syphilis.