You are all set to bank your baby’s cord blood. You have your cord blood collection kit ready and have discussed it with your OB–GYN. You chose the best cord blood bank, Cryo-Cell International, which uses an advanced collection kit to properly transport your baby’s cord blood and has a processing method proven to extract more stem cells. What could go wrong?
Factors in a Good Cord Blood Collection
Unfortunately, there are a number of ways that your doctor or midwife may not be able to get a large volume of cord blood after delivery. As noted in our guide to the various numbers behind a cord blood collection, increases in the volume of cord blood often correlate with increases in the number of stem cells available for extraction during processing. This is not always the case—in some circumstances a smaller collection will yield more stem cells than a slightly larger collection—but it is a good rule of thumb.
Factors that have been shown to negatively affect the volume of cord blood include the following:
- Lower baby delivery weight (also related are pre-term delivery, intrauterine growth restrictions, maternal hypertension and the baby's sex)
- Multiple gestations (i.e., multiple births and later children)
- Abnormal placentation
- Inter-facility transfer
- Fast-moving third stage
There are other factors, on the other hand, associated with the collection of more cord blood:
- Absence of obstetrical complications
- Patience by the provider when drawing the blood
- Clamping the umbilical cord within 30 seconds of delivery
- Birth by Caesarean section
- Skin-to-skin contact following delivery
- Performing a collection before the placenta has been delivered, or while in-utero.
A cord blood collection bag can hold a little more than a cup of blood
Increases in the baby’s delivery weight correlate with both a larger cord blood collection and a higher number of cells, with some estimates that every pound of additional weight equates to a 28% increase in stem cells. Certain circumstances, however, are often associated with a lower delivery weight and are thereby linked to a lower volume of cord blood and fewer stem cells.
Intra-uterine growth restrictions, hypertension in the mother and the baby being female are all associated with smaller collections, but these may have more to do with those factors’ impact on delivery weight than the impact of those factors alone.
Preterm babies are also often associated with smaller collections, but gestational age only correlates with lower volumes and may actually have an inverse relationship with the number of stem cells. In other words, preterm collections, such as those from 36 week to 37 weeks of gestation, have been found to have more stem cells despite having less cord blood than babies closer to term.
Mutiple gestations comes in two forms. In our blog about cord blood banking for twins or multiples, we noted how twins or triplets often collect less cord blood overall but still enough for banking:
"We received 10% less cord blood in multi-birth collections than single-birth collections, but multiple-birth collections still had nearly 4 times more cells and nearly 8 times more CD34+ stem cells post-processing than the minimums we require."
Multiple gestations can also refer to previous births; lower collection volumes are often found in later children. The reason is not known.
Other Medical Concerns
Abnormal placentation, a change in the medical facility and a fast-moving third stage of delivery have all also been shown to correlate with lower cord blood collection volumes. It is easy to understand why any sort of irregularity to the birthing process could have an impact on the collection because ensuring the mother’s and baby’s safety is always the first priority.
The absence of obstetrical complications, on the other hand, has been associated with larger cord blood collections. Lack of complications goes hand in hand with ancedotal evidence from nurses that a bit of patience will help collect more cord blood.
Emergency Caesarean sections may capture less cord blood but more stem cells
Vaginal vs. Caesarean Section
While it’s true that emergency Caesarean sections often acquire less cord blood, it’s also been shown that those smaller collections may have a higher number of stem cells. This may be due to the mobilization of more stem cells during situations of infant distress.
In our article about misconceptions about Caesarean sections and cord blood banking, we noted that non-emergency Caesarean sections have been shown to actually acquire more cord blood than their vaginal counterparts. Some researchers speculate that C-sections may collect more cord blood because the baby is raised higher above the placenta following delivery.
Placing the newborn on the mom’s abdomen right after delivery is associated with a significantly larger cord blood collection. As with the C-Section, this may be because it places the baby above the placenta, changing the flow of blood.
Delayed Cord Clamping
Delayed cord clamping (DCC) is the practice of not clamping the umbilical cord immediately following delivery but rather clamping after it continues to pulse. The American College of Obstetricians and Gynecologists (ACOG) recommends delaying the clamping of the umbilical cord for 30–60 seconds for all healthy infants. Keeping the delay to just 30 seconds, however, may help ensure a large cord blood collection. (Read Delayed Cord Clamping and Cord Blood Banking for further insights.)
Researchers have also looked at whether it was better to collect cord blood before or after placental delivery. It was found that an in-utero collection of cord blood increased the chance that more cord blood would be collected.
Everyone wants the best cord blood collection possible, but there are many factors that can affect the volume of cord blood collected and thus the number of stem cells available. While many of these factors are out of the parents’ hands, being aware of these circumstances can help them make informed choices and better understand the outcomes that may result.