Embryogenesis is an incredible phenomenon. It begins with fertilization and implantation of the blastocyst into the uterine wall, followed by development of the extraembryonic membrane which gives rise to the placenta, which is, literally, the lifeblood of the fetus. Although physicians often focus on the health of the placenta during pregnancy, the umbilical cord is an equally important organ.
The umbilical cord acts as a conduit through which metabolic products and biproducts, such as nutrients, antibodies, iron, and blood, pass bidirectionally between a mother and her baby. Many problems can arise if the cord becomes altered. For example, true umbilical cord knot is associated with small-for-gestational-age fetuses, premature birth, neonatal intensive care unit admissions, and fetal death (Int. J. Gynaecol. Obstet. 2013;122:18-21). In addition, short or long cord length may lead to fetal heart rate anomalies and higher risk for birth asphyxia (J. Obstet. Gynaecol. India. 2012;62:520-5).
While the health of the umbilical cord during pregnancy closely correlates to successful outcomes, the cord’s functions conclude at birth. Physicians clamp the umbilical cord at parturition as a routine part of the delivery process. Many ob.gyns. may not even stop to think about cord clamping. To borrow the phrase from the old Nike slogan, they “just do it.”
However, exactly when physicians should clamp the umbilical cord remains a topic for debate. Should ob.gyns. clamp the cord immediately or shortly after birth? Proponents of immediate clamping might argue that waiting too long could cause an influx of placental* blood in the neonate, leading to risk for jaundice. Those on the side of delayed cord clamping might say that waiting to terminate the cord prevents the baby’s oxygen supply from being prematurely cut off. Also, how long should the delay last: One minute? Two minutes? More? Less?
Clearly, the issue of cord clamping requires discussion. Therefore, we have devoted the first Master Class of 2015 to this important topic. We have invited Dr. George A. Macones, the Mitchell and Elaine Yanow Professor and Chair, and director of the division of maternal-fetal medicine and ultrasound in the department of obstetrics and gynecology at Washington University, St. Louis, to explore the debate. As the recent vice chair for the Committee on Practice Bulletins – Obstetrics for the American College of Obstetricians and Gynecologists, Dr. Macones has a unique perspective on the arguments for and against immediate or delayed cord clamping, as well as significant experience as a practicing ob.gyn. and leader at a vibrant academic medical center.
Dr. Reece, who specializes in maternal-fetal medicine, is vice president for medical affairs at the University of Maryland, Baltimore, as well as the John Z. and Akiko K. Bowers Distinguished Professor and dean of the school of medicine. Dr. Reece said he had no relevant financial disclosures. He is the medical editor of this column. Contact him at [email protected].
Correction, 4/14/15: An earlier version of this article misstated the potential consequences of waiting too long to clamp the umbilical cord.