Parturition Flashcards
What are the 7 cardinal movements of parturition?
- Engagement
- Descent
- Flexion
- Internal rotation
- Crowning
- Extension
- External rotation
Describe engagement
Occurs when the largest diameter of the fetal head fits into the largest diameter of the maternal pelvis. As the head engages it moves towards the pelvic brim in either the left or right occur-transverse position.
Describe descent
Baby descends through the pelvic inlet towards the pelvic floor.
What causes descent?
Uterine contractions, amniotic fluid pressure and abdominal muscle contraction
How is descent measured?
By ischial spines
Describe flexion
As fetal head comes into contact with pelvic floor the fetal neck flexes (chin to chest) to sub-occipitobregmatic position to reduce circumference
Describe internal rotation
The pelvic floor has a gutter shape (a forward and downward slope) which allows the head to rotate from left/right occipto-tranverse to occipto-anterior position.
Describe crowning
Occurs when the widest diameter of the fetal head successfully negotiates through the narrowest part of the maternal body pelvis (head is visible at the vulva and doesn’t retreat between contractions)
Describe extension
The occiput (back of head) slips beneath the suprapubic arch as the head extends and the nape of the neck pivots around the arch
Describe external rotation
The head externally rotates to face the right or left medial thigh of the mother. (restitution also occurs where the shoulders rotate from a transverse position to an anterior-posterior position to realign with the head)
Which stage of parturition causes the perineum to stretch?
Extension
After external rotation what can the midwife do to help deliver the baby?
Pressure the head up and down to wiggle the shoulders free
