Answer: The assessment of the umbilical cord at birth that would be most important to help detect congenital heart defects is d. Number of blood vessels in the umbilical cord.
Explanation: The umbilical cord contains blood vessels that connect the developing fetus to the placenta, supplying oxygen and nutrients. The normal umbilical cord consists of two arteries and one vein, forming a three-vessel cord.
However, in some cases of congenital heart defects, there may be an abnormality in the number of blood vessels within the umbilical cord. For example, certain heart defects, such as single umbilical artery (SUA), can result in the absence or reduction of one of the arteries. SUA is associated with an increased risk of other structural anomalies, including congenital heart defects.