During a medical procedure, the difference between 30 and 60 seconds often is critical only for emergency situations. But a new study supports the idea that cutting the umbilical cord slightly later is better for the newborn baby and poses no harm to the mother.
Most doctors, as described by the New York Times, generally clamp and sever the umbilical cord within one minute of birth. This the-quicker-the-better approach has been thought to reduce the risk of the mother hemorrhaging. But the new study, published in The Cochrane Database of Systematic Reviews found that waiting at least a minute after birth to clamp the cord allows more blood flow from the placenta, improving the baby’s iron and hemoglobin. There was no additional risk of severe postpartum hemorrhage, blood loss or reduced hemoglobin levels to the mother.
The Cochrane review analyzed data from 15 randomized trials involving 3,911 women and infant pairs.
The Times’ story indicates that the timing of clamping—which occurs in two places along the umbilical cord, the cut to be made between the clamps—has been controversial for a long time.
The Cochrane paper showed higher hemoglobin levels 24 to 48 hour after birth in newborns whose cords were clamped later. These babies also were less likely to be iron-deficient three to six months after birth, compared with term babies who had earlier cord clamping. Birth weight also was significantly higher in the late clamping group, partly because babies received more blood from their mothers.
The World Health Organization (WHO) recommends clamping of the cord from one to three minutes after birth, according to The Times, because it “improves the iron status of the infant.” Sometimes, delayed clamping can cause jaundice in infants because of liver trouble or an excessive loss of red blood cells. The WHO says that where later clamping is practiced, jaundice treatment should be available.
As noted in our backgrounder, jaundice is an uncommon type of birth-related brain injury; the yellow skin signaling jaundice means the baby has too much bilirubin, the yellowish color in bile, in his or her blood.
A committee of the American College of Obstetricians and Gynecologists last year reviewed much of the same evidence as the Cochrane study, but came to a different conclusion from the WHO. It found the material “insufficient to confirm or refute the potential for benefits from delayed umbilical cord clamping in term infants, especially in settings with rich resources.”
The committee said that the risks of jaundice and the relative infrequency of iron deficiency in the U.S. meant that the long-standing practice of immediate clamping should not be changed.
There are circumstances in which early clamping is required—if an infant requires resuscitation or aspirates its own stool. The new analysis found a 2% increase in jaundice among babies who got delayed cord clamping. Those babies should tested three to five days after birth.
Dr. Eileen Hutton, a midwife who teaches obstetrics at McMaster University in Ontario and published a systematic review on cord clamping, said the Cochrane report was “comprehensive and well done,” but she would have preferred a conclusion that was even stronger in favor of delayed cord clamping.
“The implications are huge,” Hutton told The Times. “We are talking about depriving babies of 30 to 40 percent of their blood at birth—and just because we’ve learned a practice that’s bad.”
Dr. Tonse Raju, a neonatologist at the National Institute of Child Health and Human Development agreed: “It’s a good chunk of blood the baby is going to get, if you wait a minute and a half or two minutes,” he told The Times. “They need that extra amount of blood to fill the lungs.”
Healthy babies manage to compensate if they do not get the blood from the cord, Raju said, but researchers do not know how.
Because the Cochrane review had few subjects who had undergone Caesarean delivery, “We don’t have enough information on the effects of delayed cord clamping for someone undergoing a Caesarean delivery in terms of postpartum hemorrhage,” Dr. Cynthia Gyamfi-Bannerman, medical director of the perinatal clinic at Columbia University, told The Times. “Waiting 30 or 60 seconds in a vaginal delivery in a low-risk patient is probably something we could do and wouldn’t have maternal consequences, but in a Caesarean delivery, you’re cutting into a pregnant uterus that has a huge amount of blood.” In some scenarios, “there’s an increased risk of postpartum hemorrhage.”
Also, there was no data on long-term neurological outcomes. But, according to The Times, improved iron stores might help reduce the risk of learning deficiencies and cognitive delay in children. Those problems have been linked to iron-deficiency anemia in school-age children.
If you are expecting, discuss the timing of cord clamping and cutting well before your due date. Your doctor or midwife should give you as complete a picture as possible of the nature of your pregnancy, and whether you and your new family member are candidates for waiting just a bit longer to cut that cord.
For more information, see our backgrounder on prenatal care.