Mechanisms Of Labour Flashcards
(15 cards)
How would you introduce yourself to Ana ?
I would say hello, say my name and role, explain what I’m going to do and wash my hands following the WHO 5 moments 7 steps hand hygiene.
Confirm details.
Discuss what approach you would take to delivering antenatal education ?
I would take an assets based approach, find out what ana already knows and build on this
Definition of mechanisms of labour ?
When the widest diameter of the fetus successfully navigates the widest part of the pelvis
Describe basic anatomy of the pelvis?
Formed into 2 parts- the true and false pelvis
The brim and above is the false pelvis and it’s not related to child birth
The cavity and the outlet forms the true pelvis, this relates to child birth
Beginning with the pelvic brim, describe its anatomy and diameters ?
Pelvic brim begins at the start and is bonded by the sacrum, the sacral promontory and the symphysis pubis at the front
Is ovoid in shape
Diameters
Anterior/ posterior = 11cm
Oblique - 12cm
Transverse- 13cm
What are the 8 landmarks ?
The sacral promontory
The sacral ala ( wing like structure)
Sacral iliac joint
The illialpectineal line
Illieal pectineal imminence
The upper border of the superior pubic Rami
Upper pubic arch
The symphysis pubis
We use these landmarks to determine fetal position in labour
Describe the pelvic outlet and diameters ?
Partially borded by ligaments and diamond in shape
Formed by the coccyx, the lower part of the symphysis pubis and ligaments
Diameters
Anterior/ posterior = 13cm
Oblique= 12cm
Transverse= 11cm
Describe the pelvic cavity and its diameters ?
Shorter at the front as it’s borded by the symphysis pubis and longer at the back as borded by sacrum.
Finishes at the coccyx.
All the diameters are the same all 12cm
Describe and demonstrate DESCENT
For a primigravida descent can happen from around 36 weeks gestation
For a paras or multi paras women descent can happen up until the onset of labour due to uterine tone
Descent is the fetus moving towards the pelvic brim
When the widest part of the fetal head enters the pelvic brim we call this engaged.
describe and demonstrate FLEXION
Flexion happens with increased descent and good contractions and fundal dominance.
Fetal axis pressure causes the fetus to push downwards and meet the resistance of the pelvic floor
Fetus then tucks their chin to their chest to present smaller diameters to progress labour
Explain and demonstrate internal rotation ?
Due to the resistance of the pelvic floor thus causes the fetus to internally rotate from a transverse position to a more anterior position
There is then a backwards and rocking motion of the presenting part at the vulva and with continued descent will move on to crowning
Explain and demonstrate crowning ?
This is where the largest diameter of the fetal head passes through the vulva and there is no longer a rocking motion.
This is what causes the ring of fire
Following crowning the baby’s head is then born by a process of extension
Explain and demonstrate extension ?
The neck pivets on the sub pubic arch and the head is born with the sweep of the forehead across the perinium followed by the nose and chin and gradually the whole head
Extension is then followed by restitution
Explain and demonstrate restitution ?
This is where the fetal head externally rotates to realign with the shoulders
This realignment helps the shoulder to pass through the pelvic outlet
External rotation of the head and internal rotation of she shoulders happens at the same time.
Explain and demonstrate lateral flexion ?
Midwife can assist if this is a hands on birth
Baby’s head will follow the curve of caries (shape of sacrum)
Midwife can use a chin occiput grip or hold side of baby’s head to gently pull downwards until the anterior shoulder is physical at the vulva
Then use an upwards motion so the posterior shoulder glides against the perinium.
Midwife then delivers baby and prepare for skin to skin and the golden hour
