What is Immediate Cord Clamping?
During pregnancy, the umbilical cord transfers oxygenated, nutrient-rich blood from the placenta to the baby. After birth, when the baby is able to breathe on its own and receive milk for nutrition, the placenta, and therefore the umbilical cord, is no longer necessary for the baby’s survival. In the wild, many mammals sever the umbilical cord with their teeth after birth, but in the human medical setting, the cord is first clamped and then cut with medical scissors. Immediate Cord Clamping (ICC) simply refers to the timing of this clamping after birth. If the cord is clamped and/or cut less than 1 minute following birth, it is considered immediate, or “early,” cord clamping.
What is the current practice toward cord clamping?
Early cord clamping originally came into practice in the 1950s as an attempt to reduce the instance of neonatal jaundice, and was used in the 1970s to facilitate resuscitation. In the 1990s, the American College of Obstetrics and Gynecology (ACOG) called for early clamping for legal purposes. Today the procedure is routinely performed by most obstetricians, while most midwives prefer delayed clamping. 
What does the evidence suggest?
Even after 50 years of use in US hospitals, there is actually no evidence to support the routine practice of immediate cord clamping. In fact, all the available research suggests that not only does ICC show no benefit to the baby, but that it actually does damage.  This is because of a phenomenon called placental transfusion, where for a period of time after birth, a healthy placenta continues to supply oxygenated, nutrient rich blood to the baby. ICC disrupts this process, which can have long-term consequences for the baby (see below).
What are the risks of immediate cord clamping?
It is estimated that at least 30% of the baby’s potential blood volume is transferred by the placenta after birth  — which means that clamping the cord early frequently results in hypovolemia (too little blood) and anemia (too little iron). Infant anemia is linked to a variety of problems, such as cerebral palsy, respiratory distress, behavioral and developmental disorders (such as autism).
“To clamp the cord immediately is equivalent to subjecting the infant to a massive hemorrhage, because almost a fourth of the fetal blood is in the placental circuit at birth.” [Windle, 1969]
Risks to the mother include an increased chance of retained placenta and postpartum hemorrhage, which can lead to some serious complications. 
What is the alternative?
In a word, waiting. Delaying the clamping of the cord to at least two minutes has been shown to prevent anemia during the first year of life, therefore reducing the risk of anemia-linked disorders during childhood. 
Although the need for resuscitation has been cited as justification for ICC, it is actually possible, if not preferable to perform resuscitation with the umbilical cord attached, since the placenta continues to provide oxygenated blood to the baby for several minutes after birth. A newborn’s lungs may not be developed enough to distribute oxygen to the body, but a healthy placenta and umbilical cord usually are. 
Babies delivered by cesarean, as well as premature infants, can also receive the benefits of delayed clamping. Research has found a significant reduction in infection and bleeding in the brain amongst preemies who received a complete placental transfusion. 
Delaying cord clamping at least two minutes is recommended by the World Health Organization. 
Immediate cord clamping has demonstrated no benefit to babies or mothers. In fact, research has shown that it actually does harm, by increasing the risk of anemia in infants, which can cause lifelong disabilities. The physiological norm is to wait until the cord has stopped pulsing before severing it — immediate clamping and cutting is an intervention that was put into practice without any evidence to support it. In the absence of such evidence, after 50 years of practice, isn’t it time we acknowledge that it may not be the right choice? Isn’t it time to admit that maybe Mother Nature knows better on this one?
Conspiracy Theory Time:
A large portion of the evidence to support delayed cord clamping has come from midwives, who have continued to practice it even as doctors advocated for immediate clamping. Ever since birth moved from the home to the hospital, and from doctors to midwives in the early 20th century, doctors (for the most part) have viewed themselves as more of an authority on birth than midwives. Could it be that doctors (as a group) have resisted the evidence in support of delayed cord clamping simply because it came from midwives? How much of this practice is because of evidence (of which there is none) and how much of it is simply defending their egos? Is the pride of doctors worth more than the health of American babies?
One of the conditions linked to immediate cord clamping is autism. Evidence suggests that babies delivered by obstetricians (more likely to perform ICC) have higher rates of autism than babies delivered with midwives (more likely to delay clamping/cutting).  What if this condition could be prevented simply by waiting an extra minute or two before clamping the cord?
Since immediate cord clamping became routine in many hospital settings, birth has become more and more medicalized. Interventions such as induction and labor augmentation have led to more diagnoses of fetal distress, as well as a higher rate of cesarean deliveries. Another change in fetal medicine since the introduction of ICC is the increasing rate of pregnancies resulting from fertility treatments. These pregnancies are more likely to result in multiples (and therefore higher likelihood of c-section) and prematurity , both of which increase a baby’s risk of requiring resuscitation. Premature, “fetal distress/asphyxia” diagnoses, and babies delivered via c-section all experience higher rates of resuscitation. Luckily, perinatologists have become more and more adept at saving these “at risk” babies, but what if there were fewer babies to save? What if doctors and women made decisions about their pregnancies and births based on evidence, and used fewer interventions? What if we took a proactive approach and made the decisions that would lead to healthy babies in the first place, rather than relying on resuscitation and other life-saving measures simply because they are available?
Most newborn procedures can be delayed or done while the baby is held by the mother, reducing the need to clamp/cut the umbilical cord. Even in the case of problems at birth, it is possible that the natural transfusion between placenta and baby could benefit the baby. Obstetricians seem to be more likely to ICC than midwives, so keep that in mind when you choose your care provider.