The favorable female pelvis for normal delivery is?

BSF Staff Nurse - 2015

Obstetrics & Gynaecology

Easy

Appeared in: BSF Staff Nurse - 2015

Explanation

The Gynecoid pelvis is the classic female type, present in about 50% of women, making it the most common.
Its key features include a round or slightly oval inlet, straight pelvic side walls, and a wide subpubic arch of approximately 90 degrees.
These characteristics provide the most spacious and direct route for the fetal head during labor, making it the most favorable type for a normal vaginal delivery.
The non-prominent ischial spines ensure the mid-pelvis diameter is adequate for fetal passage.

Option A: The Android pelvis, or 'male' pelvis, has a narrow, heart-shaped inlet and a narrow subpubic arch. These features constrict the pelvic outlet, making it unfavorable for vaginal delivery and increasing the risk of labor arrest.
Option C: The Anthropoid pelvis has a long, oval inlet (anteroposteriorly). While vaginal delivery is possible, it often leads to the fetus being in an occiput-posterior position, which can result in a longer and more difficult labor.
Option D: The Platypelloid pelvis is flat and wide, with a short anteroposterior diameter. This shape makes it very difficult for the fetal head to engage in the pelvis, often leading to failure to progress and the need for a Cesarean section.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Caldwell-Moloy classification of female pelvic types and their obstetric significance as background academic context rather than a clinical decision trigger.
Clinical or radiological assessment of the pelvic type (pelvimetry) can help healthcare providers anticipate potential difficulties during labor and delivery, guiding management decisions.
A woman identified with an Android or Platypelloid pelvis has a higher likelihood of cephalopelvic disproportion (CPD), requiring closer monitoring for labor progress and a potentially lower threshold for operative delivery.
What if? If a woman has an Anthropoid pelvis, the nurse should be prepared for a potentially longer labor and anticipate an occiput-posterior fetal position. This may require encouraging specific maternal positions (e.g., hands and knees, side-lying) to facilitate fetal rotation and descent.

How to Approach the Question

Identify the keywords in the question: 'favorable female pelvis' and 'normal delivery'.
Recall the four main types of pelvis from the Caldwell-Moloy classification: Gynecoid, Android, Anthropoid, and Platypelloid.
Remember the basic shape and characteristic of each type: Gynecoid (round, 'classic female'), Android (heart-shaped, 'male'), Anthropoid (long oval), and Platypelloid (flat oval).
Associate the 'classic female' round shape (Gynecoid) with the most suitable and accommodating dimensions for childbirth.
Eliminate the other types based on their less favorable shapes: Android (narrow outlet), Anthropoid (promotes malposition), and Platypelloid (prevents engagement). This leads to Gynecoid as the correct answer.

Concept Tested & Keywords

Concept Tested: Caldwell-Moloy classification of female pelvic types and their obstetric significance.
Stem keywords: favorable female pelvis, normal delivery
Lead-in keywords: is
Clinical cues: Age/sex group narrows the expected diagnosis, intervention, or normal reference range.

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

E6 Obstetrics Williams p. 16-32