The average length of the umbilical cord is?

IGNOU Post B. SC. Nursing entrance-2019

Obstetrics & Gynecology

Easy

Appeared in: IGNOU Post B. SC. Nursing entrance-2019

Explanation

Authoritative pediatric textbooks state that at term, a normal umbilical cord is approximately 55 cm long.
The typical range for umbilical cord length is wide, but most cords measure between 50 and 60 cm.
Among the given choices, 56 cm is the most accurate representation of the average length cited in major medical literature.

Option A: While some sources cite 50 cm as an average and it falls within the normal range, it is on the lower end of the typical 50-60 cm range. More authoritative sources cite the average as being closer to 55 cm.
Option B: This value is within the normal range for umbilical cord length but is less representative of the accepted average (approximately 55 cm) than other options.
Option C: This is very close to the accepted average of 55 cm. However, 56 cm is an equally valid, if not slightly better, approximation given that the average is often cited as 55-60 cm.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy and average length of the umbilical cord as background academic context rather than a clinical decision trigger.
Assessing the umbilical cord at birth is a key nursing responsibility. This includes checking for the presence of three vessels (two arteries, one vein, often remembered by the mnemonic 'AVA').
Abnormal cord length is associated with specific risks. A short cord (less than 35 cm) can lead to fetal distress or cord rupture, while a long cord (greater than 70 cm) increases the risk of true knots and prolapse.
What if? If only a single umbilical artery (SUA) is found, the infant should be thoroughly examined for other congenital anomalies. SUA is associated with a 20-30% risk of other structural defects, particularly affecting the cardiac and renal systems.

How to Approach the Question

This is a factual recall question that requires knowledge of standard anatomical measurements in obstetrics.
First, recall the typical range for umbilical cord length at term, which is generally cited as 30-100 cm, with most falling between 50-60 cm.
Recognize that questions asking for an 'average' of a biological measurement often refer to the midpoint of the most common range.
The midpoint of the 50-60 cm range is 55 cm. Authoritative texts confirm the average is approximately 55 cm.
Evaluate the given options (50, 52, 54, 56 cm) to determine which is closest to the accepted average of 55 cm.
Both 54 cm and 56 cm are very close. Since 55-60 cm is a common range, 56 cm is a strong and accurate choice representing this average.

Concept Tested & Keywords

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E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 1141-1143

E6 Midwifery Obstetrics and Gynecology Nursing Sandeep Kaur p. 56-70