Parturition - Phases

Question 1

Phases

• Name of phase
• General description

Answer 1

• Phase 1
  
  • Quiescence
  • Prelude to parturition
• Phase 2
  
  • Activation
  • Preparation for labor
• Phase 3
  
  • Stimulation
  • Process of labor
• Phase 3
  
  • Involution
  • Parturient recovery
• Memory aid:*
• QuASI

Question 2

Phase 1

• Name
• General description
• When
• Uterus
• Cervix

Answer 2

• Name
  
  • Quiescence
• General description
  
  • Prelude to parturition
• When
  
  • Begins even before implantation
• Uterus
  
  • Contractile unresponsiveness
  • Braxton-Hicks contractions may be felt
• Cervix
  
  • Maintenance of cervical structural integrity despite cervical softening, increased vascularity and stromal hypertophy

Question 3

Phase 2

• Name
• General description
• When
• Uterus
• Cervix

Answer 3

• Name
  
  • Activation
• General description
  
  • Preparation for labor
• When
  
  • During the last 6-8 weeks of pregnancy
• Uterus
  
  • Myometrial unresponsiveness suspended
  • Formation of LUS → lightening
• Cervix
  
  • Cervical ripening, effacement and loss of structural integrity

Question 4

Myometrial changes in the activation phase is attributable to:

Answer 4

Expression of contraction-associated proteins

• ↑ uterine irritability
• ↑ responsiveness to uteronins
  
  • Connexin 43
  • Oxytoxin receptor
  • Prostaglandin F

Question 5

Treatment to:

• Prevent premature cervical ripening
• Promote cervical ripening

Answer 5

• Prevent premature cervical ripening
  
  • No therapies
• Promote cervical ripening
  
  • Prostaglandin E₂ (PGE₂) and PGF_2α
  • Progesterone antagonist

Question 6

Prostaglandin MOA

Answer 6

Modify extracellular matrix structure to aid ripening

Question 7

Phase 3

• Name
• General description
• When
• Uterus
• Cervix

Answer 7

• Name
  
  • Stimulation phase
• General description
  
  • Processes of labor
• When
  
  • Active labor
• Uterus
  
  • Uterine contractions
• Cervix
  
  • Cervical dilation

Note: It also includes fetal and placental expulsion (3 stages of labor)

Question 8

Phase 4

• Name
• General description
• Uterus
• Cervix

Answer 8

• Name
  
  • Involution phase
• General description
  
  • Parturient recovery (puerperium)
• Uterus
  
  • Uterine involution
• Cervix
  
  • Cervical repair

Question 9

Of the 4 phases of parturition, phase 2 is characterized by which of the following?

1. Uterine activation, cervical ripening
2. Uterine quiescence, cervical softening
3. Uterine involution, cervical remodelling
4. Uterine contraction, cervical dilatation

Answer 9

Answer: 1

• Uterine activation, cervical ripening

Rationale:

• 2 - phase 1
• 3 - stage 4
• 4 - stage 3

Question 10

Collagen changes in phase 1 vs phase 2

Answer 10

• Phase 1 (softening)
  
  • altered collagen processing and the number/type of covalent cross-links between collagen triple helices
  • reduction in cross-links between newly synthesized collagen monomers
• Phase 2 (ripening)
  
  • fibril diameter increased
  • space between fibrils increased and disorganized
  • dispersion of collagen fibrils resulting to loss of tissue integrity and increased compliance

Question 11

Phase of parturition that corresponds to the clinical stages of labor

Answer 11

Phase 3