Female Pelvis

Flashcards about Female Pelvis & Fetal Skull

Pelvic Diameters

Measured at 3 levels: Brim (Inlet), Cavity (Mid-pelvis), Outlet

Brim (Inlet) Key Diameters

Anteroposterior (True conjugate) ~11 cm

Transverse ~13 cm

Oblique (R & L) ~12 cm

Cavity (Mid-pelvis) Key Diameters

~12 cm all around (roughly circular)

Outlet Key Diameters

Anteroposterior ~13 cm

Transverse (bituberous) ~11 cm

Gynaecoid Pelvis

Rounded brim, Balanced AP:Transverse Ratio (AP ~11 cm, Transverse ~13 cm), Roomy, rounded walls, Wide outlet, Favors occipito-anterior position (OA), ~50% of women

Android Pelvis

Heart-shaped brim, Narrow AP:Transverse Ratio (~10 cm), Funnel-shaped, narrow cavity, Reduced risk of arrest in descent, OP common, deep transverse arrest, ~20%

Anthropoid Pelvis

Oval brim - long AP, AP longer (~13 cm), transverse shorter (~11 cm), Deep cavity, Adequate outlet, OP common but birth often possible, ~25%

Platypelloid Pelvis

Flat pelvis - wide transverse brim, Short AP (~10 cm), very wide transverse (~14 cm), Shallow cavity, Narrow AP diameter outlet, Head may not engage, Rare (~5%)

Gynaecoid Labour Consideration

Most favorable, spontaneous vaginal birth likely

Android Labour Consideration

May require operative delivery (forceps/CS)

Anthropoid Labour Consideration

OP more likely, but vaginal birth often successful

Platypelloid Labour Consideration

Difficult engagement – may need C-section