Labor and Birth Process

Factors affecting labor

• Power (contractions)

• Passageway (birth canal)

• Passenger (fetus and placenta)

• Position of mom

• Psychological response

Power

Primary powers

• Contrations

  • frequency, duration, intensity

• Effacement

• Dilation

• Ferguson relex

Secondary powers

• Bearing-down efforts

Passageway

Composed of

• Bony pelvis

• Soft tissue

• Pelvic floor

• Vagina

• Introitus (external opeing of vagina)

Pelvis types

• Gynecoid (the classic female type)

• Android (resembling the male pelvis)

• Anthropoid (resembling the pelvis of anthropoid apes)

• Platypelloid (the flat pelvis)

Passenger

• Size of fetal head

• Fetal presentation

  • cephalic

  • breech

  • shoulder

• Fetal lie

• Fetal attitude

  • flexion

  • extension

• Fetal position (relation to pelvis)

  • station (progress of descent)

  • engagemnet

Position

frequent changes in position

• relieve fatigue

• increase comfort

• improve circulation

Psychological response

Emotional state determines response and affects physiological function

Anxiety and fear, slow progression and increase pain

Prelabor

• irregular contractions

• no progress

• no effect on dilation/effacement/descent

• contractions felt in abd and groin

• relieved by activity (walking)

True labor

• regular contractions

• longer, stronger, closer together

• back pain

• progress in dilation and effacement

• engagement occurs and descent takes place

Stages of labor

Frist stage

Second stage

Third stage

Fourth stage

First stage

onset of regular contractions to full dilation

- Latent and active phase

Second stage

Full dilation to birth of baby

- Pushing

Third stage

Birth of fetus until delivery of placenta

Fourth stage

2 hrs post delivery of placenta

Mechanism of labor

• Engagement & Descent

• Flexion

• Internal Rotation of the head

• Extension

• Restitution

• External Rotation

• Expulsion

Physiological adaptations to labor - Fetal

Fetal

• Fetal heart rate( 110-160 bpm)

• Fetal circulation

• Fetal respiration

Physiological adaptations to labor - Maternal

Maternal

• Cardiovascular changes

• Respiratory changes

• Renal changes

• Integumentary changes

• Musculoskeletal changes

• Neurological changes

• Gastrointestinal changes

• Endocrine changes