Active stage
Full cervical dilatation and pushing (abdo muscles and valsalva)
Comfortable position (squatting, standing, all fours, supine, etc)
Not all diameters of foetal head can pass through the pelvis,
so adaptation in a well defined pattern must occur;
attendant must stabilise the perineum and foetal head
Engage and descend: head engages, descends in OL with inc flexion
Internal rotation: to OA at ischial spines (aided by AI sloping of lev ani)
Crowning: head extends, distends the perineum and anus
Resitution: rotation of head so occiput in line with foetal spine (back to OL)
Ext rotation: shoulders rotate as reach lev ani
Ant shoulder delivery: posterolateral trunk flexion, under pubic arch
Post shoulder delivery: anterolateral trunk flexion