This document summarizes phases 3 and 4 of parturition or labor and delivery. Phase 3 involves 3 stages: first stage is labor with uterine contractions and cervical changes like effacement and dilation; second stage is fetal descent through the birth canal; third stage involves separation of the placenta and its delivery. Phase 4 is the postpartum or puerperium period. Key regulators of phases 3 and 4 are discussed, including oxytocin, prostaglandins and other hormones from the uterus and surrounding tissues.

1. PHASES OF PARTURITION 3 & 4
Dr. Indraneel Ashok Jadhav
MBBS, DGO, DNB
Consultant Gynecologist and IVF
Indira IVF, Kolhapur
BY INDRANEEL ASHOK JADHAV

2. Phase 3 of parturition : Labor
BY INDRANEEL ASHOK JADHAV

3. FIRST STAGE :
 Show
 Uterine contractions
Hypoxia of myometrium
Compression of nerve ganglia
Cervical stretching
Ferguson reflex
Stretching of peritoneum
BY INDRANEEL ASHOK JADHAV

4.  Formation of distinct Lower and upper
uterine segments :
1. UPPER SEGMENT :
Actively contracting
Becomes thicker as labor advances
Quite firm or hard
2. LOWER SEGMENT :
Relatively passive
Develops into a much thinly walled passage
for the fetus
Much less firm
BY INDRANEEL ASHOK JADHAV

5. FORMATION OF LOWER AND UPPER
UTERINE SEGMENTS
BY INDRANEEL ASHOK JADHAV

6. Physiological retraction ring
Pathological retraction ring
Changes in uterine shape
 Ancillary forces
 Cervical changes
Effacement
Dilatation
BY INDRANEEL ASHOK JADHAV

7. CERVICAL CHANGES :
BY INDRANEEL ASHOK JADHAV

8. CERVICAL CHANGES IN PRIMI AND MULTI
BY INDRANEEL ASHOK JADHAV

9. CERVICAL CHANGES :
BY INDRANEEL ASHOK JADHAV

10. SECOND STAGE OF LABOR :
FETAL DESCENT
 Station
Division of labor course on the basis of expected
evolution of dilatation and descent :
Preparatory division
Dilatational division
Pelvic division
 Pelvic floor changes
BY INDRANEEL ASHOK JADHAV

11. FETAL DESCENT IN RELATION TO
CERVICAL DILATATION :
BY INDRANEEL ASHOK JADHAV

12. THIRD STAGE OF LABOR :
BY INDRANEEL ASHOK JADHAV

13.  Fetal membrane separation and placental
extrusion
BY INDRANEEL ASHOK JADHAV

14. Placental separation :
Schultze mechanism
Duncan mechanism
BY INDRANEEL ASHOK JADHAV

15. PHASE 4 OF PARTURITION :
Puerperium
BY INDRANEEL ASHOK JADHAV

16. REGULATION OF PHASES 3 & 4 :
 Uterine stimulation
Role of Oxytocin
Role of Prostaglandins
Endothelin 1
Angiotensin 2
 Contribution by intra uterine tissues
BY INDRANEEL ASHOK JADHAV

17. THANK YOU
BY INDRANEEL ASHOK JADHAV

18. Thank You
BY INDRANEEL ASHOK JADHAV