Stages Of Labor

1. STAGES OF NORMAL LABOR

2. CRITERIA FOR NORMAL LABOUR
 Spontaneous expulsion,
 Of a single, Mature fetus (37-42 weeks),
 Presented by vertex,
 Through the birth canal (vaginal delivery),
 Within a reasonable time,
 Without complications to the mother,
 Without complications to the fetus.

3. STAGES OF LABOUR

4. FIRST STAGE OF LABOUR
 It starts with regular and rhythmic uterine contractions till completion
of full cervical dilatation (10cm).
 Aims at :-
o Dilatation and effacement of the cervix
o Full formation of lower uterine segment
 DURATION : For primi gravida 16hrs to 18hrs.
For multi gravida 6hrs to 10hrs.

5. • Latent phase
Onset –regular contractions
Ends –3 cm of dilatation
Prolonged latent phase->20 hours in the nullipara, >14 hours in the
multipara

6. Active phase
Onset –cervical dilatation of 3 cm
Protraction –slow rate of cervical dilatation
Arrest –complete cessation of dilatation or descent

7. MATERNAL PROGRESS IN I STAGE OF LABOR
Criteria Latent phase Active phase Transition phase
Duration
Primi gravida
Multi gravida
8 – 10 hrs
5 hrs
3 – 6 hrs
4 hrs
2 hrs
1 hr
Contraction
Strength
Rhythm
Frequency
Duration
Mild – Moderate
Irregular
5 – 30 mts
30 – 45 seconds
Moderate – Strong
More regular
3 – 5 mts
40 – 70 seconds
Strong – Very strong
Regular
2 – 3 mts
45 - 90 seconds
Cervical dilatation 0 – 3 cm 4 – 7 cm
1.2 cm / hr in Primi
1.5 cm / hr in Multi
8 – 10 cm
1 cm / hr in Primi
2 cm / hr in Multi
Station of the head
Primi gravida
Multi gravida
0
-2 to 0 cm
+2 cm
+1 to +2 cm
+3 and above
Show Brownish Pale pink
discharge
Pink to bloody
mucus
Bloody mucus

8. EVENTS IN 1ST STAGE OF LABOUR

9. Factors responsible :-
 Uterine Contraction :- While the upper segment contracts , retracts
and pushes the fetus the lower segment dilate in response to forces of
contraction of upper segment.
 Retraction:- the quality of uterine muscle fiber remains shortened
after contracting during the labour. This results in a gradual
progression of the fetus downward through pelvis.
 Fetal axis pressure :- With longitudinal lie and well fitted fetal head
on cervix the upper segment contraction force is transmitted to the
lower pole causing mechanical stretching of lower segment and
dilation.

10.  Bag of Membranes
 As the lower uterine segment forms and stretches
, the chorion becomes detached from it and the
increased intrauterine pressure causes its
loosened part of the sac of fluid to bulge
downward into the internal os, to the depth of 6-
12 mm.
 The well flexed head fits into the cervix and cuts
off the fluid in front of the head from that which
surrounds the body.
 The former is known as ‘forewaters’ and the latter
the ‘hindwaters’.

11.  Formation of Physiological Retraction Ring
 A distinct ridge is produced at the junction of upper
and lower uterine segment due to progressive
thickening of upper segment and thinning of lower
uterine segment. Pronounced in late first stage
• A Pathological retraction ring is formed in obstructed labor.

12. PHASES OF 2ND STAGE OF LABOUR
 LATENT PHASES / PROPULSIVE PHASE :
 Descend of the fetus 2 cm below from the os to the pelvic floor .
 ACTIVE PHASES / EXPULSIVE PHASE :
Descend of the fetus from the os 2cm below to the vaginal outlet (
Crowning )
 Ferguson reflux : Pressure exerted by the presenting
part over the cervix causing involuntary uterine contraction
 TRANSITION PHASES / COMPULSIVE PHASE :
Birth of the baby from the vaginal outlet till extension .

13. RUPTURE OF MEMBRANES
 The optimal physiological time for the membranes to
ruptures spontaneously is at the end of the first stage of
labour after the cervix becomes fully dilated and no longer
supports the bag of forewaters.

14. SECOND STAGE OF LABOUR
 It begins with full cervical dilatation (10cm) till the
birth of the baby.
 DURATION :
 Primi gravida - 2 hours.
 Multi gravida - 30 minutes.

15. RECOGNITION OF COMMENCEMENT
OF II STAGE OF LABOUR
 Expulsive uterine contraction
 Rupture of the fore waters
 Dilatation and gaping of anus
 Appearance of present part
 Congestion of the vulva

16. PHYSIOLOGY OF II STAGE OF LABOUR
 I Uterine action
 Contraction becomes stronger, longer but less frequent.
 Membranes rupture spontaneously.
 Consequent drainage of liquor allows the hard, round fetal head to be directly
applied to the vaginal tissues and aid distension.
 Fetal axis pressure increasing the flexion of the head which results in smaller
presenting diameter ,more rapid progress and less trauma to both mother and
fetus.
 Expulsive contraction:- irresistible desire to ‘bear down’ and push until baby is
delivered , added by voluntary contraction of abdomen (bearing down efforts) .
 Propulsive contraction :- from full dilation until head touches the pelvic floor
 Involuntary uterine contraction.

17. II Soft tissue displacement :
 As the hard fetal head descend, the soft tissue of the
pelvis become displace.
 Anteriorly the bladder is pushed upwards into the
abdomen which cause stretching and thinning of the
urethra.
 Posterioly the rectum becomes flattened into the
sacral curve and the pressure of the advancing head
expels any residual faecal matter.
 Laterally the Levator ani Muscles dilate and thins out
and perineal body is flattened ,displaced ,stretched
and thinned.

18. THIRD STAGE OF LABOUR
 Begins after delivery of the baby and ends with the delivery of the
placenta and membranes
 It contains two phases
A. Separation
B. Expulsion

19. BEFORE SEPARATION
Per abdomen:
 Uterus become discoid in shape, firm in feel and ballottable.
 Fundal height reaches slightly below the umbilicus.
Per vaginum:
 There may be slight trickling of blood.
 Length of the umbilical cord as visible from outside remains static.

20. AFTER SEPARATION
 Per abdomen:
 Uterus become globular, firm and ballottable.
 fundal height is slightly raised.
 supra pubic bulging
 Per vaginum:
 Slight gush of vagina bleeding.
 Permanent lengthening of the cord.

21. MECHANISM OF SEPARATION
 Marked retraction in the size of uterus causes buckling of inelastic
placenta which brings about its separation.
 The plane of separation runs through deep spongy layer of decidua
basalis.
 Central Seperation (Schultze) :- Detachment of placenta from it’s
uterine attachment starts at centre resulting in opening of sinuses and
accumulation of blood , this weight also facilitates placental
separation.
 Marginal Separation (Mathews- Duncan) :-Separation starts from
margin and is unsupported , more frequently observed.

22.  DESCEND OF THE PLACENTA
 Sudden trickle or gush of blood.
 Lengthening of the umbilical cord.
 Change in the shape of the
uterus, globular.
 Change in the position of the uterus.

23.  Expulsion of Placenta :-
 After complete separation of placenta, it is forced down into the flabby
lower uterine segment or upper part of vagina by effective contraction
and retraction of uterus.
 It is expelled out by either voluntary contraction of abdominal muscles
(bearing down efforts) or by manual procedures.

24. HEMOSTASIS
 After placental separation , innumerable torn sinuses having free
circulation have to be obliterated.
 Retraction of the oblique uterine muscle fibres leading to clamping of
arterioles.
 vigorous uterine contraction following placental separation.
 transitory activation of the coagulation and fibrino-lytic systems.