Incidence of gynecoid pelvis in females is about?

Appeared in: AIIMS Delhi NO - 2017

Explanation

The gynecoid pelvis is the most prevalent type of female pelvis, occurring in about 50% of women.
Its anatomical structure, featuring a rounded inlet, spacious cavity, and a wide subpubic arch (greater than 90 degrees), is optimally shaped for the passage of the fetal head.
Due to these favorable characteristics, it is considered the ideal pelvic type for a spontaneous vaginal delivery with the fewest complications.

Option A: This figure is excessively high. No single pelvic type is found in 90% of the female population, as there are four distinct classifications.
Option B: This is incorrect as it implies all females have an identical pelvic structure. The Caldwell-Moloy classification identifies four different types of pelvises, each with a different prevalence.
Option C: This percentage overestimates the prevalence of the gynecoid pelvis. While it is the most common type, it only accounts for approximately half of the cases, not nearly three-quarters.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Incidence and classification of female pelvic types (Caldwell-Moloy classification) as background academic context rather than a clinical decision trigger.
Nurses and midwives assess pelvic type during antenatal care to anticipate potential difficulties during labor and delivery.
A non-gynecoid pelvis, particularly the android or platypelloid types, increases the risk of cephalopelvic disproportion (CPD), which can lead to obstructed labor and the need for a Cesarean section.
What if? If a woman is identified as having a platypelloid pelvis (5% incidence), the nurse should anticipate a higher likelihood of the fetal head engaging in a transverse position, which can lead to arrest of descent and require operative delivery.

How to Approach the Question

Recognize that the question is asking for a specific factual value related to female anatomy and obstetrics.
Recall the different types of female pelvis (Caldwell-Moloy classification) and their approximate frequencies.
Remember that the gynecoid pelvis is the 'classic' or 'typical' female pelvis and is the most common, but not the only type.
This knowledge helps eliminate extreme answers like 90% and 100%, as biological traits with known variations rarely occur with such high uniformity.
Between the remaining options, select the value that represents 'most common' but not an overwhelming majority, which is approximately 50%.

Concept Tested & Keywords

Concept Tested: Incidence and classification of female pelvic types (Caldwell-Moloy classification).
Stem keywords: Incidence, gynecoid pelvis, females
Lead-in keywords: is about

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E6 Midwifery Obstetrics and Gynecology Nursing Sandeep Kaur p. 38-46

E6 Obstetrics Williams p. 16-33

Practise the full AIIMS Delhi NO - 2017

Attempt every question from this paper in a timed mock, then review the full solution for each one.