The document outlines the mechanism of labor, detailing the series of events that occur to expel the fetus through the vagina. It explains three key principles: descent, rotation of the leading part, and pivoting around the pubic bone, and uses mnemonics to aid memory. Additionally, it describes the principle movements such as engagement, descent, flexion, and various rotations necessary for a successful labor process.

1. MECHANISM OF LABOUR
JASLEEN KAUR
MSc.(N)

2. DEFINITION
Series of events that takes place on genital organ in
an effort to expel the viable product of conception out
of the womb through vagina into the outer world.

3. PRINCIPLES
There are three principles of mechanism of
labour.
a) Descent takes place throughout labour.
b) Whichever part leads and first meets the
pelvic floor will rotate forward until it comes
under symphysis pubis.
c) Whatever part emerges from the pelvis will
pivot around pubic bone.
Nemonics DSP (descent, symphysis pubis and
pubic bone) to remember principles of
mechanism of labour.

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5. CRITERIA FOR NORMAL
MECHANISM OF LABOUR
• Lie is longitudinal
• Presentation cephalic
• Position ROA or LOA
• Attitude is good flexion
• Denominator is occiput
• Presenting part is posterior part of anterior
parietal bone

6. PRINCIPLE MOVEMENTS IN NORMAL
MECHANISM OF LABOUR
• Engagement
• Descent
• Flexion
• Internal rotation of head
• Crowning
• Extension of head
• Restitution

7. PRINCIPLE MOVEMENTS IN NORMAL
MECHANISM OF LABOUR
• Internal rotation of shoulders
• External rotation of head
• Delivery of body by lateral flexion
Nemonics to remember mechanism of labour
END FLICER ICED (flicer means very bright ) so flicer
company ke end hone se uska manaager iced ho gya.

8. PRINCIPLE MOVEMENTS IN NORMAL
MECHANISM OF LABOUR
• Engagement
– Engages with sagittal sutures in right oblique and
biparietal diameter in left oblique
– Occiput points to left ileo pectineal eminence
• Descent
– Fetus descent due to contraction and retraction of
uterine muscle
• Flexion
– Engaging diameter is sub occipito frontal (10cm)
– Changes to sub occipito bragmatic (9.5cm)

9. Engagement

10. • Internal rotation of head
– Occiput is the leading part
– Rotates one by eighth of the circle
– Sagittal suture comes in APD
– Slight twist in the neck of the fetus
• Crowning
– Biparietal diameter stretches at vulval outlet
• Extension of head
– Releases Sinciput face and chin
– Head is born by flexion
• Restitution
– Twist in the neck of the fetus is corrected by slight untwisting
movement
– Occiput turns one by eighth of the circle towards the maternal
side

11. Crowning

14. • Internal rotation of shoulders
–Shoulders rotate one by eighth of a circle to lie
under symphysis pubis
• External rotation of head
–Occiput rotates further one by eighth to the
mothers left side
• Delivery of body by lateral flexion
–Anterior shoulder escapes under symphysis pubis
–Posterior shoulder sweeps the perineum
–Body is born by lateral flexion

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