Professor, Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora
Dr. Hobbins reports no financial relationships relevant to this field of study.
Synopsis: Although a recent study has failed to show major benefit from delayed umbilical cord clamping, others have suggested neonates having delayed cord clamping have less need for transfusion, higher hematocrits, less neonatal morbidity, and diminished risk of intraventricular hemorrhage.
Source: Elimian A, et al. Immediate compared with delayed cord clamping in the preterm neonate. Obstet Gynecol 2014;124:1075-1079.
The question of whether to clamp the umbilical cord immediately or to wait for a boost of blood from the placental/cord reservoir has been debated, seemingly, forever, and recommendations by various medical organizations have been inconsistent. Many studies have emerged that address the issue, but the authors’ concluding statements often end in a call for more investigation, especially in preterm pregnancies. Elimian et al have answered the call with another recently published randomized controlled trial (RCT).1
The study focused on the need for neonatal transfusion in preterm neonates. Two hundred patients delivering between 24 and 32 weeks were randomized. In 99 patients, the umbilical cords were clamped 30 seconds following delivery and in 101 patients clamping occurred immediately after delivery. Although the decision for transfusion was based on the general clinical picture, it was mostly employed in those neonates whose hematocrits were < 30%.
There were no significant differences between groups, with 25 of the “delayed cord clamping” (DCC) group (25.3%) and 24 of the “early” group (ECC) needing transfusions (23.7%; P = 0.8). The mean gestational ages in the groups were the same (30.7 weeks vs 30.8 weeks), and there were no significant differences in respiratory distress syndrome, necrotizing enterocolitis, or periventricular leukomalacia. However, the hematocrits were significantly higher in the DCC group (51% vs 47%), and there was a nonsignificant trend in a lower rate of intraventricular hemorrhage (IVH) compared with the ECC group (11.1% vs 19.8%).
Table 1 lists the often-postulated pros and cons of delayed clamping. Regarding the incidence of postpartum hemorrhage, a Cochrane database review has shown no difference between ECC and DCC.2 Studies in term babies, including the above Cochrane review, have shown a 50% decrease in neonatal anemia with a significant decrease in the need for transfusion.2 In addition, there has been a significant increase in ferritin stores noted at 6 months of age.3 On the downside, with DCC there is an increased rate of asymptomatic polycythemia and hyperbilirubinemia, resulting in a slightly heightened need for phototherapy.2
Table 1: Pros and Cons of Delayed Clamping
- The addition of 50-160 mL of placental blood (with added RBCs) represents as high as a 30% increase in blood volume — a bonus especially for preterm neonates, who generally run at least a one in four chance of needing transfusion(s).
- There would be an additional boost of up to 50/mg/kg of iron.
- The placenta contains 30% of the stem cells in the fetal circulation, which would be left behind with ECC. These could be invaluable in any infant’s ability to fight infection.
- Some studies have shown a significant decrease in intraventricular hemorrhage with DCC.
The delay may increase the risk of postpartum
- The delay may prevent infants from getting immediate stabilizing care and predispose them to hypothermia and hypoxia.
- The added boost in red cells could cause neonatal polycythemia, jaundice, and an increased need for phototherapy.
The regimen could interfere with parents’ desires
for the collection of cord blood for later stem cell purposes.
- It would simply lengthen the time needed to complete the entire delivery process, a factor that particularly comes into play during cesarean section.
The featured study’s negative transfusion results are out of sync with most other studies, which, in addition to showing the beneficial findings noted above, have noted better circulatory stability,4 improved general neonatal outcomes,5 and, in particular, a 50% decrease in IVH with DCC.6
Medical organizations have varied somewhat in their recommendations. The World Health Organization (WHO) has advocated for DCC in all pregnancies,7 based on less need for transfusions and an increase in iron stores at 6 months of age — features particularly important in locations with limited resources. The American College of Obstetrics and Gynecology (ACOG)8 has waffled on DCC in term pregnancies (“insufficient evidence”), but has supported its use in preterm pregnancies, mostly because of decreased IVH. Regarding cord blood banking, the ACOG document states that “the desire to collect blood should not interfere with, or determine the timing of, cord clamping.” The American Academy of Pediatrics has simply endorsed the ACOG stance.
Other ways to potentially provide a blood volume/red cell/stem cell bonus to the infant:
- Using gravity to enhance transfer of blood — An earlier study suggested better transfer of blood during DCC when the baby is positioned at the level of the placenta, rather than on the mother’s abdomen (based on the average placental weights in each group after DCC).9 This is undoubtedly why the WHO recommended this step. In contrast, a very recent study, using infant weights as surrogate indicators of delta blood volumes, found no difference between the two methods of infant positioning during DCC.10 The obvious benefit of the second method is the skin-to-skin contact with the mother.
- Cord “milking” for vaginal deliveries (as an alternative to DCC) — A very recent study from one institution showed a substantial increase in hematocrit, a decreased need for transfusion, and improved composite neonatal outcome when a milking regimen for all vaginal deliveries was initiated (compared with a historical control group).11
- Milking/stripping for cesarean sections — An RCT showed improvement in neonatal outcome when the umbilical cords were stripped during cesareans.12
- Waiting until the cord stops pulsating — While representing the ultimate in non-intervention, little data are available comparing this practice with other options.
It appears that ECC is the most common practice today. Why? Here is one answer from a review by Mercer et al.13 “In the last century as technology advanced, respect for the process of birth has been lost in exchange for efficiency and expedience.” On one hand, we demand that new techniques pass “evidence-based” scrutiny, but we are slow to abandon practices that have sneaked in through the side door simply because they are more convenient. So, in view of the somewhat conflicting results in the literature, what is a clinician to do? A reasonable stance would be to go with the most “natural” approach (DCC) because:
- The majority of single studies and meta-analyses have shown neonatal benefit of DCC in almost every category.
- There is a major theoretical advantage to a bolus of stem cells from placental/cord blood.
- There is no evidence of any real harm to mother or infant.
- Elimian A, et al. Obstet Gynecol 2014;124:1075-1079.
- McDonald SJ, Middleton P. Cochrane Database Syst Rev 2008;CD004074.
- Hutton KH, Hassan ES. JAMA 2007;279:1241-1252.
- Rabe H, et al. Cochrane Database Syst Rev 2012;CD003248.
- Backes CH, et al. Obstet Gynecol 2014;124:47-56.
- March MI, et al. J Perinatal 2013; 33:763-767.
- World Health Organization. http://www.who.int/nutrition/publications/guidelines/cord_clamping/en/. http://www.who.int/elena/titles/cord_clamping/en/.
- Committee on Obstetric Practice, American College of Obstetricians and Gynecologists. Opinion No. 543: Obstet Gynecol 2012;120:1522-1526.
- Yao AC, Lind J. Biol Neonate 1974;25:186-193.
- Vain NE, et al. Lancet 2014;384:235-240.
- Patel S, et al. Am J Obstet Gynecol 2014;211:519.e1-7.
- Erickson-Owens DA, et al. J Perinatal Nurs 2012; 32:580-4.
- Mercer JS. J Midwifery Womens Health 2001;46:402-412.