I am working on the chapter on managing third stage, the time between the birth of the baby and the delivery of the placenta, for the new edition of Ob Myths Versus Research Realities. As some of you may have noticed, I almost never make recommendations outright about medical interventions, but immediate cord clamping demands that I make an exception to my rule:*
I strongly recommend that couples INSIST that the cord not be clamped until it has stopped pulsing. Immediate clamping of the umbilical cord deprives the baby of 25% to 40% of its blood volume.
As one reviewer (Mercer 2002) says, "In other circumstances, . . . such a massive restriction in blood volume would result in severe consequences, even death." It is a testament to the resilience of the birth process that most babies do OK despite this, although that may not apply to preemies. Nonetheless, randomized controlled trials clearly show that immediate cord clamping has short- and long-term adverse effects on the baby's hematologic status. More babies will have anemia as much as 6 months later. In addition, Mercer makes a strong case based on physiology and animal studies that initiation of respiration "is based on and driven by adequate blood volume." Specifically, expansion of the alveoli in the lung depends on blood filling and stiffening the capillary networks that surround them.
Mercer JS, Skovgaard RL. Neonatal transitional physiology: a new paradigm. J Perinat Neonatal Nurs 2002;15(4):56-75.
What about the baby who needs resuscitation? The usual practice is to cut the cord, and rush the baby away for treatment. This makes no sense. As long as the cord is pulsing, the baby is still receiving oxygen from the mother, and leaving the cord attached provides a grace period. Equipment should be brought to the baby, not vice versa.
One might wonder how this practice came about in the first place. It was based on the theory that hypervolemia (getting too much blood) would increase risk of jaundice, polycythemia (too high a red blood cell count), and respiratory difficulties. None of this has been shown to occur. A recent systematic review concluding that clamping should be delayed takes note of what it calls "asymptomatic polycythemia." But the norms for this have been based on values with immediate clamping. This is like setting newborn growth curves based on formula-fed babies and saying breastfed babies don't gain weight fast enough. What we have is not babies with "asymptomatic polycythemia," we really have babies currently considered normal who are actually suffering from hypovolemia and anemia. And leaving aside the research, if you think about it, on logical grounds alone, it is always a bad idea to interfere routinely with a functioning physiologic process.
Hutton EK, Hassan ES. Late vs early clamping of the umbilical cord in full-term neonates: systematic review and meta-analysis of controlled trials. JAMA 2007;297(11):1241-52.
By the way, allowing the baby to recover its full complement of blood is good for mom too. Emptying the engorged placenta helps it to detach more efficiently and effectively.
*The other exception is to refuse induction with misoprostol (Cytotec).