UMBILICAL CORD BLOOD UNIT
Factors Influencing the Quality of Umbilical Cord Blood Unit for Banking: Are Maternal Age, Blood Volume, Birth Weight and Birth Order Important for Umbilical Cord Blood Banking
Introduction
Umbilical cord blood used to be rendered useless and discarded. However, current evidence shows that cord blood can form an essential part of the hematopoietic system if collected shortly after birth. Research is revealing that the process of collecting the blood is straightforward and does not cause any risk to the baby or mother. Besides, the process has a low risk of graft versus host disease or transmission of infections and contagious diseases. The cord blood is a vital alternative of hematopoietic stems cells used in the treatment of various immune system, blood, and genetic illnesses (Boo, Ballen, & Maiers 2011; Nunes & Zandavalli 2015). The use of umbilical cord blood has increased in the recent past since the first successful case of the treatment of Fanconi’s anemia in 1988. Beksac (2016) suggests that over three million units of umbilical cord blood are in current storage internationally for potential use in the treatment of diverse medical conditions. According to Idris, Nordin, Mahdy, and Wahid (2018), umbilical cord blood has many unique aspects that make it beneficial as a treatment procedure for many illnesses, such as large-scale availability. It can multiply better than marrow and peripheral blood and easily reconstruct the Haematopoietic pool of the host. Therefore, it can be used in various transplantations with significant health benefits for patients.
Regardless of the benefits drawn from the use of the umbilical cord blood, specific factors should be considered to determine its viability. Idris et al. (2018) reveal several limitations evident in the use of umbilical cord blood. The authors indicate that a single unit of umbilical cord blood is not sufficient in hematopoietic stem cell numbers and might fail in transplantations targeting adults. Some studies suggest that the dosage of the hematopoietic stem cells required for such transplantation should be around “1 × 107 to 3 × 107 nucleated cell count/kg recipients” (Idris et al. 2018, p. 2491). Further evidence indicates that a CD34+ cell dose of less than 1.7 × 105 /kg had a high risk of death” (p. 2492). Consequently, the Umbilical cord blood banks have established a policy to choose high-quality donations to ensure that the blood is sufficient and viable for use for transplantation purposes even in adults. Various factors are considered to determine the quality aspects of the blood for use to save lives.
Research has been conducted to develop the necessary guidelines for the collection of viable and useful umbilical cord blood immediately after birth and the storage appropriate for transplantation. The guidelines include the factors that are necessary to achieve the objectives of quality umbilical cord blood (Idris et al. 2018). They should also ensure that umbilical cord blood banks meet the needs for sufficient blood and enjoy the benefits that the treatment process has promised in clinical practice. Although it might be argued that the umbilical cord blood is a viable alternative of hematopoietic stems cells, it has a major limitation regarding the amount of blood collected from this part of the human body (Allan, Petraszko, Elmoazzen, & Smith, 2013). Besides, other possible factors are evident, which might affect the viability of umbilical cord blood collection, including maternal age, blood volume, birth weight, and birth order.
Factors that Might Affect the Viability of Umbilical Cord Blood
Blood Volume
Various factors affect the blood volume obtained from the umbilical cord. Research shows that the mode of delivery, either natural birth of cesarean section delivery affects the volume of blood collected from the umbilical cord. Abdelrazik et al. (2015) established that cesarean section delivery provides a higher level of blood from the umbilical cord. However, it is possible that the effect on the blood volume has nothing to do with the mode of delivery, but instead the method of collecting the blood. Idris et al. (2018) revealed that cord clamping might be a critical aspect of the volume of umbilical cord blood. If the person clamping the cord maintains a long length with the placenta, there might be a considerable volume of blood compared to when a short length is sustained. In addition, when a short interval between the placenta delivery and the collection of the blood is evident, it is possible to receive more blood compared with when there is a delay between the two processes. Besides, other possible reasons for the difference are available, such as the placental weight, with a larger cord having the potential to provide more blood compared with smaller ones. Thus, the volume of the blood collected depends on the various neonatal and maternal factors.
Previous studies reveal the tenable collection, preservation, and use of umbilical cord blood for the treatment of various medical conditions in babies and adults. In their research, Chivu et al. (2007) established a collection of 46 umbilical cord blood units. They conducted the study to determine the sufficiency of the collected blood in a particular geographic region. The results of the investigation affirmed that the volume of the blood depended on factors such as gestation length and the weight of the newborn (Yang, Loutfy, Mayerhofer & Shuen 2011). They used the multiple regression models, which revealed that the two variables are critical as well as significantly related to the increase in the total nucleated cells from umbilical cord blood (p<0,001) (Chivu et al. 2007). Therefore, during umbilical cord blood collection, it is essential to consider other factors that affect the volume. They should capitalize on the births that will ensure sufficient umbilical blood for collection, preservation, and future usage.
Healthy Pregnancy
A healthy pregnancy is considered as one of the most critical factors that determine the viability of umbilical cord blood for collection and use. It might also include the health of the mother and the child by the time of birth. Idris et al. (2018) suggest that regardless of the possibility of this factor playing a significant role in the collection and use of umbilical cord blood, little research is conducted on the effects of common ailments that complicate pregnancy such as gestational diabetes mellitus (GDM) and preeclampsia (PE). Potentially, the blood might become untenable if such conditions compromise the health of the mother. However, from their study, Idris et al. (2018) concluded that medical conditions during pregnancy, such as gestational diabetes mellitus (GDM) and preeclampsia (PE) affect the quality of umbilical cord blood hematopoietic stem cell. Therefore, the nucleated cell count numbers of pregnancies affected by the conditions were lower than the global standards for healthy pregnancies. Thus, the health of the mother during pregnancy determines the quality and volume of umbilical cord blood collected.
Maternal Age
Regardless of the health of the pregnant woman, other factors such as the age of the mother might determine the viability of the cord blood. Idris, Nordin, Mahdy, and Wahid (2018) suggested the possibility that younger maternal age leads to high-quality umbilical cord blood. Notably, younger donors are always more preferable compared with older ones. Research shows that people who register as potential donors become unviable years later unless they provide the blood immediately (Spellman et al. 2012). Possible delays in their donation affect the feasibility of the umbilical cord blood due to various changes in their circumstances. Age is one of the factors that might change with time and affect the viability of the collected blood (Solomon, Wofford, Johnson, Regan & Creer 2010). Therefore, maternal age should be considered when selecting potential donors for the umbilical cord blood, and if possible, choose younger mothers because of the volume and quality of the blood.
Birth Order
The viability of umbilical cord blood might be affected by the birth order. For example, inherited disorders and conditions affect the potential for blood collection and use (Hough et al. 2016). The factor plays a critical role in the selection of umbilical cord blood for transfusion and transplantation. The birth order provides crucial information on the possibility of hereditary diseases in family history (Chivu et al., 2007). While such conditions might not be immediately apparent in first births, they can be determined in subsequent deliveries. If a sibling has a hereditary condition, it might compromise the viability of umbilical cord blood from other births that follow (Page et al. 2014). The possibility is a risk factor in umbilical cord blood to be used in the treatment of various medical conditions. Therefore, birth order is a significant factor in determining the viability of the collection of umbilical cord blood.
The birth order also plays a vital role in determining the quality of umbilical cord blood because the most viable and quality donation is from the first or second births. The factor significantly affects the total nucleated cell number and CD34+ cell numbers. Chivu et al. (2007) claim that the best result universal recommendations for the umbilical blood collection suggest the need for the blood to be obtained from mothers with their first or second babies. Therefore, the quality declines as the mother continues to give birth to subsequent babies. Umbilical cord blood banks should capitalize on the first births and collect adequate blood for storage and future use. However, the argument does not suggest that donations for other deliveries, after first and second, are entirely unviable. If the bank can collect viable blood from later births, then it can be beneficial for clinical use. However, they should capitalize on the first two births.
Birth Weight
High infant and placenta weight are other factors that have been considered as the potential to provide high-quality umbilical cord blood. The aspects are some of the neonatal variables that correlate with high umbilical cord blood. Births of bigger babies have been considered as important aspects in the collection of the high volume of umbilical cord blood. The “NETCORD standards for UCB harvesting, processing, testing, selection and storage” suggest that, for viability, the pregnancy must be ≤ 40 weeks and the weight of the baby should be more than 3600 grams (Chivu et al., 2007, p. 185-186). The review further indicated that for clinics that collect umbilical cord blood immediately after the delivery of the placenta, its weight might affect the volume and quality of the blood. Sufficient umbilical cord blood units depend on the weight of the placenta because it also relates to the weight of the newborn. Therefore, they determine the volume of the blood that can be collected. For example, for a placental weight that is more than 700 g, it is possible to obtain a sufficient volume of umbilical cord blood. However, the factor does not provide a valid criterion for clinics that harvest the blood before the delivery of the baby. Hence, the weight of the newborn could be a more useful condition in the collection of umbilical cord blood.
The Newborn’s Sex
The sex of the newborn might be an essential factor in determining the adequacy and quality of umbilical cord blood. According to Chivu et al. (2007), a previous study conducted by Aroviita P and Solves P revealed that, the number of nucleated cells is considerably higher in umbilical cord blood collected from female newborns. Besides, they revealed differences in the CD34+ number drawn from the two genders. However, some studies reveal no significant difference in the volume and quality of umbilical cord blood drawn from the two sexes. Other studies suggest that male newborns provide quality umbilical cord blood compared to females, in terms of CD34+ cell content. The suggested difference in absolute concentration is about 5.3% (Chivu et al. 2007). Therefore, the effect of the sex of the newborn on the volume and quality of the blood remains controversial, and hence requires further exploration.
Major Possibilities in Umbilical Cord Blood
Significant advancements are allowing the use of umbilical cord blood without the traditional limitations such as a mismatch. Nikolajeva (2017) suggests that safer protocols have been developed in the collection and use of umbilical cord blood that enable the use of mismatched donors. The T-cell replete haploidentical transplantation is a major possibility in the use of umbilical cord blood as an alternative to conventional sources of blood for transfusion (Wall & Chan 2008). The strategy is appealing to medical practitioners because of the ease of collection and the potential of getting a donor for every patient at a moderate cost. The National Marrow Donor Program® (NMDP) and The Center for International Blood and Marrow Transplant Research® (CIBMTR) facilitate the recognition and collection of unrelated donations for hematopoietic cell transplantation (HCT) (Dehn et al. 2019). Therefore, regardless of controversies surrounding the vital factors to consider in the quality and volume of umbilical cord blood, it remains a viable source of grafts for transfusion and transplantation.
Conclusion
The umbilical cord is increasingly being used as a safer and less costly alternative source of HSC for transplantation. However, it is crucial to understand the obstetric and maternal factors that have a significant impact on the volume, quantity, and quality of umbilical cord blood. Therefore, clinics that draw the blood for preservation and later use should consider the critical factors to save on the cost of untenable blood and to ensure that potential recipients have the possibility of obtaining quality blood. However, it is essential to perform additional research on the factors that remain controversial in terms of their effect on the quality and volume of the blood, such as the sex of the newborn, weight, and the possible consequences of the maternal health condition during pregnancy.