The approximate average weight of the placenta at birth is?

Appeared in: AIIMS Patna NO - 2020

Explanation

The average weight of a human placenta at full term is approximately 500 grams.
This weight typically corresponds to a feto-placental weight ratio of about 6:1, meaning the placenta is roughly one-sixth the weight of the fetus.
The normal range for placental weight at term is generally considered to be between 400 g and 600 g.
The placenta's dimensions are also standardized, with a diameter of 15-20 cm and a central thickness of about 2.5 cm.

Option A: This weight is significantly below the average and the normal range for a term placenta. A 300 g placenta would be considered small and is often associated with placental insufficiency and fetal growth restriction.
Option B: This weight is at the lower limit of the normal range (400-600 g) for a term placenta but does not represent the average weight.
Option D: This weight is at the upper limit of the normal range. While a 600 g placenta can be normal, it is not the average. A weight of 600 g or more can be associated with conditions like maternal diabetes or fetal hydrops.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Normal physiological characteristics of the placenta at term as background academic context rather than a clinical decision trigger.
Assessing placental weight after delivery is a crucial part of the postpartum examination. It provides valuable information about the intrauterine environment and fetal health.
A small placenta (less than 400 g) can be an indicator of placental insufficiency, which may have led to intrauterine growth restriction (IUGR).
A large, heavy placenta (greater than 600 g) can be associated with maternal conditions like diabetes mellitus, severe anemia, or infections (e.g., syphilis), and fetal conditions like hydrops fetalis.

How to Approach the Question

First, identify the keywords in the question: 'average weight' and 'placenta at birth'.
This is a factual recall question that requires knowledge of normal physiological values in obstetrics.
Recall the standard measurements for a term placenta, specifically its average weight.
Compare the recalled value with the given options to select the closest and most accurate answer.
Eliminate options that are significantly too low (300 g) or represent the upper end of the normal range (600 g) rather than the average.

Concept Tested & Keywords

QeUL51VzleISBe0Sm9g9q

E6 Midwifery Obstetrics and Gynecology Nursing Sandeep Kaur pp. 60-74, 51-62

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