Which of the following is a common type of female pelvic shape with features such as round, shallow and open?

UP CHO - 10 September 2021

Obstetrics & Gynaecology

Easy

Appeared in: UP CHO - 10 September 2021

Explanation

The Gynecoid pelvis is the typical female pelvis, found in approximately 50% of women.
Its key features include a rounded pelvic inlet, a shallow and spacious pelvic cavity, and a wide subpubic arch (greater than 90 degrees).
These anatomical characteristics provide the most ample space for the fetal head to navigate through the birth canal, making it the most favorable shape for a spontaneous vaginal delivery with the fewest complications.

Option A: The Platypelloid pelvis is characterized by a flat, wide, and transversely oval inlet. It has a short anteroposterior diameter, which can make it difficult for the fetal head to engage in the pelvis.
Option B: The Android pelvis is the typical male pelvic shape and is described as heart-shaped or triangular. It has a narrow subpubic arch and prominent ischial spines, which can obstruct fetal descent and lead to a higher rate of operative deliveries.
Option D: The Anthropoid pelvis has an oval-shaped inlet that is wider in the anteroposterior diameter than in the transverse diameter. While vaginal birth is often possible, this shape frequently leads to the fetus being in an occiput-posterior (OP) position.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of female pelvic shapes (Caldwell-Moloy classification) and their implications for labor and delivery as background academic context rather than a clinical decision trigger.
Nurses perform pelvimetry as part of the antenatal assessment to evaluate the adequacy of the maternal pelvis for vaginal delivery. This helps in identifying women who may be at risk for cephalopelvic disproportion (CPD).
Knowledge of pelvic types allows the nursing staff to anticipate labor patterns. For example, a woman with an Android pelvis may experience a slower, more difficult labor, requiring closer monitoring and potential intervention.
What if? - If a woman in labor has an Android pelvis and the fetal head fails to descend despite strong contractions, the nurse should anticipate the need for an operative delivery (forceps, vacuum, or cesarean section) and prepare accordingly, while providing support to the patient.

How to Approach the Question

First, identify the key descriptive words in the question stem: 'round,' 'shallow,' and 'open.'
Recall the four main types of female pelves as classified by Caldwell and Moloy: Gynecoid, Android, Anthropoid, and Platypelloid.
Associate the keywords with the known characteristics of each pelvic type.
Gynecoid is known for being round and spacious, making it ideal for childbirth.
Android is heart-shaped and narrow, typical of a male pelvis.
Anthropoid is oval-shaped in the anteroposterior dimension.

Concept Tested & Keywords

Concept Tested: Classification of female pelvic shapes (Caldwell-Moloy classification) and their implications for labor and delivery.
Stem keywords: female pelvic shape, round, shallow, open
Lead-in keywords: Which of the following
Clinical cues: Age/sex group narrows the expected diagnosis, intervention, or normal reference range.
Negative lead-in flag: false

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

E6 Obstetrics Williams p. 16-32