Mechanism of Labor

• Mechanism of Labor:

  Mnemonics: EDFIRE ERE
• Mechanism of Labor:

  Sequence:

  Engagement - descent - flexion - internal rotation - extension - external rotation (restitution or shoulder rotation) - expulsion
• Engagement


  Fetal presenting part
• Descent


  Fetal head descends to the maternal pelvis

  Note: No descent - no other mechanism
• Flexion


  Preparation of fetal head to pass the cervix
• Internal Rotation 


  Actual passage of fetal head to the cervix
• Extension


  Expulsion of fetal head
• External Rotation 


  Expulsion of the fetal shoulder

  Note: no external rotation = shoulder dystocia
• Expulsion


  Expulsion of the fetus