Nongynecoid

Nongynecoid is a term used in anatomy and obstetrics to describe a pelvis that is not of the gynecoid shape. The gynecoid pelvis is traditionally considered most favorable for vaginal delivery, while nongynecoid pelves refer to alternative morphologies that differ from this classic pattern.

Common nongynecoid pelvic types include android, anthropoid, and platypelloid. The android pelvis is often described as heart-shaped and relatively narrow in certain dimensions; the anthropoid pelvis is oval with a longer anteroposterior diameter; and the platypelloid pelvis has a wider transverse diameter and a shallower birth canal. In practice, individual variation exists, and some individuals may exhibit hybrid or atypical pelvic configurations that do not fit a single category.

In obstetric labor, pelvic shape can influence mechanics of descent and progression. Nongynecoid pelves may be associated with different labor patterns and, in some cases, higher rates of intervention, depending on fetal size, position, and other factors. However, outcomes are highly individualized, and modern obstetric care emphasizes comprehensive assessment rather than reliance on a single pelvic classification.

Pelvic assessment historically included pelvimetry to estimate inlet size, using clinical measurements or imaging. Today, pelvimetry is used selectively, and management decisions focus on the overall clinical picture, including fetal status and labor dynamics, rather than pelvis type alone.