The document provides a comprehensive overview of normal labor, defining it as a physiological process involving spontaneous uterine contractions that lead to the expulsion of viable products of conception. It outlines the phases of labor, characteristics of normal labor, and the physiological mechanisms involved, including uterine contractions and retraction, as well as the roles of hormones in facilitating labor. Additionally, it addresses management during different stages of labor, including monitoring and interventions to ensure maternal and fetal well-being.

1. NORMALLABOUR
Presented By – Atul Yadav (RN,RM)
For more info. – medicalexpertcare.blogspot.com

2. INTRODUCTION
Labor is a physiologic process during which the
products of conception (ie, the fetus,
membranes, umbilical cord, and placenta) are
expelled outside of the uterus.

3. DEFINITION OFNORMALLABOUR
Series of events that take place in the genital
organ in an effort to expel the viable(alive)
products of conception out of the womb/uterus
through vagina into outer world is called
NormalLabour.

4. DEFINITION OFNORMALLABOUR
Labour is defined as the presence of regular
uterine contractions with progressive cervical
dilatation and effacement.

5. CRITERIA/CHARACTERISTICSOF
NORMALLABOUR
1. Spontaneous in onset and at term ( between 37
-40 weeks ofgestation.)
2. With Vertex presentation
3. Without any undue prolongation.
4. Without any complications.
5. Naturally Terminated with minimal aid.

6. PHYSIOLOGYOFNORMALLABOUR
Physiology of normal labour complete into two
steps -
UTERINE
CONTRACTION
RETRACTION

7. PHYSIOLOGYOFNORMALLABOUR
1. Uterinecontraction :
During contraction, uterus becomes hard and
somewhat pushed anteriorly to make the long axis
of the uterus in the line with that of pelvic axis.

8. PHYSIOLOGYOFNORMALLABOUR
1. Uterinecontraction :
Simultaneously, the patient experiences pain which
is situated more on the
hypogastric region, often radiating to the thighs.

9. PHYSIOLOGYOFNORMALLABOUR
1. Uterine contraction:
Probable causeof pain are –
a) Myometrial hypoxia during contractions.
b) Stretching of the peritoneum over the fundus.
c) Stretching of the cervix during dilatation.
d) Compression of the nerve ganglion.
The pain of uterine contractions is distributed along the
cutaneous nerve distribution of T10 to L1.

10. PHYSIOLOGYOFNORMALLABOUR

11. PHYSIOLOGYOFNORMALLABOUR

12. PHYSIOLOGYOFNORMALLABOUR
INTENSITY–
The intensity of uterine contractions describes the
degree of uterine
systole.
The intensity gradually increases with advancement
of labour until it
becomes maximum in the second stage during
delivery of the baby.
Intrauterine pressure is raised to 40-50 mm Hg
during first stage and about 100-120 mm Hg in the
second stage of labour during contractions.

13. PHYSIOLOGYOFNORMALLABOUR

14. PHYSIOLOGYOFNORMALLABOUR
DURATION
In the first stage, the contractions last
for about 30 second initially but
gradually increases in duration with
the progress of labour.
Thus in the second stage, the
contractions last longer than in the
first stage.

15. PHYSIOLOGYOFNORMALLABOUR
FREQUENCY
In the early stage of labour, the
contractions come at intervals of ten to
fifteenminutes.
The intervals gradually shorten with
advancement of labour until in the
second stage, when it comes every
two or three minutes.

16. PHYSIOLOGYOFNORMALLABOUR

17. PHYSIOLOGYOFNORMALLABOUR
Retraction -
Retraction is a phenomenon of the
uterus in labour in which the muscle
fibers permanently are shortened.

18. PHYSIOLOGYOFNORMALLABOUR

19. PHYSIOLOGYOFNORMALLABOUR
Unlike any other muscle of the body,
the uterine
have this property to
muscles
become
shortened once and for all.

20. PHYSIOLOGYOFNORMALLABOUR
Contraction is a temporary reduction in
length of the fibers, which attain their full
length during relaxation.
In contrast, retraction results in permanent
shortening and the fibers are shortened
once and for all.

21. PHYSIOLOGYOFNORMALLABOUR
Theneteffectofretractononnormal
labour are:- -
Essential property in the formation
of lower uterine segment and
dilatation and
effacement up of the cervix.

22. PHYSIOLOGYOFNORMALLABOUR

23. PHYSIOLOGYOFNORMALLABOUR
To maintain the advancement of the presenting
part made by the uterine contractions and to
help in ultimate expulsion of the fetus.
To reduce the surface area of the uterus
favouring separation of placenta.
Effective haemostasis after the separation of the
placenta.

26. Exercise :-
1. Define normal labor ?
2. Character tics of normal labor?

27. Pathophysiology of labor

28. NORMAL LABOR/
EUTOCIA
spontaneous in onset and at term
with vertex presentation
without undue prolongation
Natural termination with minimal aids
without having any complications affecting the
health of the mother and/or the baby

30. ESTROGEN
Increases release of oxytocin from maternal
pituitary
Promotes synthesis of myometrial receptors for
oxytocin,PGincrease in gap junctions in
myometrial cells
Stimulates synthesis of myometrial
contraction protein  actinomyosin through
cAMP.
Increases excitability of myometrial cell

31. PROSTAGLANDIN
Initiates and maintain labor
Major site of production:
Amnion,chorion, decidual cells and
myometrium
Enhances gap junction formation
Triggered by estrogen, glucocorticoids,
separation or rupture of membrane

32. OXYTOCIN
Peptide hormone
Hypothalamus-posterior pituitary
Fetal production: Maternal serum increase in
second stage of labor
Oxytocin receptors: Fundal location, increase
during pregnancy
Actions
1. Stimulate uterine contractions
2. Stimulate PG production from amnion/decidua

33.  TRUE AND FALSE LABOR
True labor
o Painful contractions at regular
intervals at term
o Contraction frequency,
intensity, duration increases
gradually
o Associated with Show
o Progressive effacement and
dilatation of cervix
o Descent of presenting part
o Formation of “bags of water”
o Not relieved by enema/
sedatives (analgesics)
False labor
o Dull pain confined to
groin and abdomen
o Pain interval doesn’t
shorten
o Pain intensity remains
same
o No cervical dilatation
o No hardening of uterus
o Relieved by enema or
sedative

34. DURING PREGNANCY…
Marked hypertrophy and hyperplasia of uterine
muscles
Length of uterus + cervix = 35 cm at term
Uterus assumes pyriform/ ovoid shape
Cervical canal occluded by thick, tenacious mucus
plug

35. UTERINE CONTRACTION IN
LABOR
Irregular involuntary painless spasmodic uterine
contraction (Braxton-Hicks) throughout pregnancy which
changes during labor
Pacemaker situated in : tubal ostia  contraction waves
initiate
Pain of contraction distributed along the cutaneous nerve
distribution of T10 –L1

36. PATTERN OF
CONTRACTIONo Good synchronization of contraction waves from both
halves of the uterus
o Fundal dominance with gradual diminishing
contraction wave through midzone down to lower
segment in 10-20 sec
o Wave of contraction follow regular pattern
o Upper segment of uterus contracts longer and
stronger than lower part
o Intra-amniotic pressure rises beyond 20mm Hg
during uterine contraction
o Good relaxation occurs in between contraction(intra-
amniotic pressure less than 8)

37. RETRACTION
Phenomenon of uterus in labor in which muscle
fibers are permanently shortened
Effects of retraction:
1. Formation of lower uterine segment + dilatation and
effacement of cervix
2. Decent of presenting part  expulsion of fetus
3. Reduce surface area  separation of placenta
4. Effective homeostasis after separation of placenta

38. STAGES OF LABOR
First phase
- latent
- Active
Second phase
Propulsive
Expulsive
Third phase
Fourth phase

39. FIRST STAGE
Concerned with formation of birth canal
Main events:
1. Dilatation of cervix
2. Effacement of cervix
3. Lower uterine segment formation

40. FACTORS RESPONSIBLE
IN DILATATION
Uterine contraction and retraction
Longitudinal fiber of upper segment
attach to circular fiber of lower
segment if uterus contracts
canal opens + shortens polarity of
uterus
Fetal axis pressure
o longitudinal lie of fetus  circular
muscles contraction transmitted
from podalic pole to head
o Not in transverse lie
Bag of membrane
Vis-a-tergo

41. EFFACEMENT OF CERVIX
“processes by which muscular fibers of cervix pulled
upward and merge with fibers of lower uterine
segment”
Primigravidae: effacement before dilation of
cervix
Multiparae: effacement and dilatation occur at
same time

42. LOWER UTERINE
SEGMENT
Formation of active upper segment and
relatively passive lower segment forms
during labor

43. Friedman’s Curve
Friedman's Curve describes progress of two variables
over time:
• dilation of cervix
• descent of baby
Labor is “dysfunctional” when cervix stops dilating or fetal
descent stops or both
Possible diagnosis of "failure to progress"
C-section indicated
May be due to CPD (Cephalo Pelvic Disproportion) or
epidural anesthesia

44. Friedman’s Curve

45. SECOND STAGE OF
LABOR
“Begins when cervical dilatation is complete and
ends with fetal delivery.”
Median duration
50 minutes in primigravida
20 minutes in multiparous
Uterine contractions and accompanying expulsive
forces last:
60-90 seconds and
recur every 60 seconds

46. Propulsive phase:
Period of full dilation until head touches pelvic floor
Expulsive phase:
Since the time mother has irresistible desire to ‘bear
down’ and push until the baby is delivered

47. DURATION OF LABOR
Mean length of 1st and 2nd stage labor
12 hours in primigravida
6 hours in multipara

48. THIRD STAGE OF LABOR
Includes separation, descent and expulsion of
placenta with its membrane.
 Signs of placental separation:
1. Hardening of uterus
2. Sudden gush of blood
3. Rise of Uterus (because the placenta, having separated, passes
down in the lower uterine segment and vagina)
4. Lengthening of umbilical cord
Signs of placental separation appear within 1-5 minutes within
delivery of newborn.

49. FOURTH STAGE OF LABOR
The placenta, membranes and umbilical cord
should be examined for completeness and for
anomalies
observation: 1 hour after birth of baby
 Laceration of birth canal(vagina and perineum):
first degree laceration
Second degree laceration
third degree laceration
fourth degree laceration

50.  Degree of Lacerations
First degree laceration:
Involved the perineal skin, vaginal mucus membrane but not underlying
fascia and muscle
2nd degree laceration:
Involve in addition, the fascia and muscle of perineal body but not anal
sphincter
3rd degree laceration:
Extent further to involve the anal sphincter
4th degree laceration:
Laceration extend through the rectum’s mucosa to exposed its lumen

51. MANAGEMENT OF FIRST
STAGE Of LABOR
1. Monitoring fetal well-being during labor
Fetal heart should be monitored every 30 mins in 1st stage
and every 15 mins in 2nd stage of labor
2. Uterine contractions
to evaluate the frequency, duration, and intensity of uterine
contractions.
3. Maternal vital signs
Maternal temperature, pulse, and blood pressure are
evaluated at least every 4 hours
with prolonged membrane rupture(>18 hours) antimicrobial
administration for prevention of group B streptococcal
infections is recommended
4. Subsequent vaginal examinations

52. CONTD..
5. Oral intake
Food should be withheld during active labor and
delivery
6. Maternal position
position that she finds most comfortable, which
will be lateral recumbency most of the time
7. Urinary bladder function
Bladder distention-avoided, because it can hinder
descent of the fetal presenting parts

53. MANAGEMENT OF SECOND STAGE
LABOR1. Preparation for delivery
 Put the patient in dorsal lithotomy position or lying flat on bed
 Clean the vulva, and perineum with antiseptic solution
 Encourage organized pushing down which she is feeling to do so
2. spontaneous delivery
 With each contraction, perineum bulges increasing
 Ritgen maneuver- when head distends the vulva and perineum
enough to open the vaginal introitus to 25 cm or more
A towel-draped ,gloved hand –used to exert forward pressure on the chin of
fetus through the perineum
 This maneuver allow delivery of head and also favors the neck
extension so that head is delivered with small diameter

54. CONT..
 Clearing the nasopharynx:
Once the thorax –delivered and the newborn can inspire
Face quickly wiped and the nares and mouth cleared
 Nuchal cord :
Found in 25% of deliveries and ordinarily no harm
If coil of umbilical cord felt-it should be slipped over the
head if loose enough
If too tight, the loop should be cut between two clamps

55. CONT...
 Clamping the cord:
Umbilical cord is cut between two clamps placed 4 to 5 cm from the foetal
abdomen and later an umbilical cord clamp-applied 2 to 3 cm from the fetal
abdomen
Plastic clamp –safe
 Timing of cord clamping:
If after delivery of the newborn –placed below the level of the vaginal
introitus for 3 min and Fetoplacental circulation – not immediately occluded
by cord clamping, then approx. 80 ml of blood shift from placenta to
neonate this reduces the frequency of iron deficiency anemia later in
infancy

56. MANAGEMENT OF THIRD
STAGE LABOR
Delivery of the placenta:
-Traction on the umbilical cord must not be used to pull the placenta
out of uterus.
-uterine inversion is one of the complication associated with delivery
Manual removal of placenta:
- Adequate analgesia is mandatory and aseptic surgical technique
should be used
-occasionally, placenta will not separate especially common in case
of preterm delivery
-if there is brisk bleeding and the placenta can not be delivered-
indicated

57. CONT...
1.Oxytocin
 Given before delivery of placenta will decrease blood loss(they
may entrap an undiagnosed, undelivered 2nd twins)
 The spontaneously labouring uterus is typically sensitive to oxytocin
and dosing should be titered to achieved adequate contraction
 After delivery of the foetus, dosing should be fixed
 It should be given as a dilute solution by continuous iv. Infusion or
im
 10 USP unit i.m. (oral not effective)
 T1/2 3-4 minutes- iv. Infusion (large bolus should not be given)

58. CONT..
CVS effect:
 IV bolus of 10 unit of oxytocin caused marked fall in BP withan
abrupt increase in CO.
 These hemodynamic changes could be dangerous for women
hypovolemic from haemorrhage or those with cardiac disease.
Water intoxication:
 Has antidiuretic action
 With high dose of oxytocin- produce water intoxication if the
oxytocin administered with large volume of electrolyte free aqueous
dextrose solution
 Oxytocin given with NS or ringer solution

59. 2. Ergonovine and methylergonovine:
 Ergot alkaloids
 Stimulation of myometrium contraction
 Given IV (0.1mg),IM or orally(0.25mg)
 They are dangerous for mother and foetus prior to delivery-
tendency of relaxation
 IV administration sometimes initiation of transient hypotension-
severe in gestational hypertension
3. prostaglandins:
 Analogs not used routinely for management of 3rd stagelabour

60. MANAGEMENT OF FOURTH
STAGE LABOR
1. Examine the placenta for their completeness,
- anomalies, ( single umbilical arteryMultiple births)
- length, and
- number of vessels in the cord and record the placental weight
 Suture the episiotomy or any laceration
 Estimate blood loss, count swabs, and take cord blood for Hb, blood
group, Rh, bilirubin, and Coomb’s test for Rh negative mother
 Check BP, P,T and firmness of the uterus before transferring the patient
 Allow no food during the first hour, sips of water may be taken

61. Diameter of skull and the way it
moves through pelvis

62. FETAL SKULL
oMade of thin pliable tabular (flat) bones
forming the vault
oCompressible to some extent
oAreas of skull:
Vertex
Brow
Face

63. o Vertex: quadrangular area bounded
anteriorly by bregma and coronal sutures
Posteriorly by lambda and lambdoid suture
Laterally by lines passing through parietal eminences
o Brow:
One side anterior fontanels and coronal sutures
Other side root of nose and supra-orbital ridges of either side
o Face:
One side root of nose and supra-orbital ridges
On other side junction of floor of mouth with neck

64. SUTURES
Frontal: between the two frontal bones
Sagittal: between the two parietal
bones
Two coronal: between the frontal and
parietal bones
Two lambdoid: between the posterior
margins of the parietal bones and upper
margin of the occipital bone

65. Diameter Measurement(cm) Attitude of
head
Presentatio
n
Suboccipito-bregmatic (nape
of neck to center of bregma)
9.5 cm Complete
flexion
Vertex
Suboccipito-frontal (nape of
neck to ant. end of ant.
fontanelle )
10.5 cm Incomplete
flexion
Vertex
Occipito-frontal(occipital
eminence to glabella)
11.5 cm Marked
deflexion
Vertex
Mento-verticle (mid point of
chin to highest point on sagittal
suture)
14 cm
(13cm in oxford
hand book)
Partial
extension
Brow
Submento-verticle (junction of
floor of mouth and neck to
highest point on sagittal suture)
11.5 cm Incomplete
extension
Face
Submento-bregmatic (junction
of floor of mouth and neck to
center of bregma)
9.5 cm Complete
extension
Face
ANTERO-POSTERIOR DIAMETER OF HEAD
THAT MAY ENGAGE

66. i. 9.5 cm
ii. Extends between two parietal eminences
a. Super-subparietal diameter:
i. 8.5 cm
ii. Extends from a point placed below one parietal eminence to a
point placed above other parietal eminence of opposite side
b. Bitemporal diameter:
i. 8 cm
ii. Distance between antero-inferior ends of coronal suture
d. Bimastoid diameter:
i. 7.5 cm
ii. Distance between tips of mastoid processes
TRANSVERSE DIAMETER
Biparital diameter:

67. Attitude of head Plane of engagement Circumference
Complete flexion Biparietal-suboccipito-bregmatic
Shape - almost round
27.5 cm
Deflexed Biparietal-occipito-frontal
Shape – oval
34 cm
Incomplete extension Biparietal-mento-vertical
Shape - bigger oval
37.5 cm
Complete extension Biparietal-submento-bregmatic
Shape - almost round
27.5 cm
CIRCUMFERENCE
Circumference of the plane of diameter of
engagement differs according to attitude of head
Circumference of head in different attitude:

68. MOULDING
“The alteration of the shape of the fore coming head
while passing through the resistant birth passage during
labor”
o There is little alteration in size of head as the volume
of content inside skull is incompressible
o An alternation of 4mm in skull diameter commonly
occur during normal delivery
o Disappears within few hours after birth

69. MECHANISM:
 Compression of engaging diameter of head with corresponding
elongation of the diameter at right angle to it
 GRADING OF MOULDING
Grade 1:
Bones touching but not overlapping
Grade 2:
Bones overlapping but easily separated
Grade 3:
Fixed overlapping of bones

70. IMPORTANCE OF MOULDING
 Slight moulding is inevitable and beneficial
Enables head to pass more easily through the
birth canal
 Extreme moulding may produce  Severe
intracranial disturbance in the form of tearing
of tentorium cerebelli or subdural
haemorrhage
 Shape of moulding gives information about
position of head occupied in pelvis

71. CARDINAL MOVEMENTS OF
LABOR

72. o the passage of the widest
diameter of the presenting part
to a level below the plane of the
pelvic inlet
o In the cephalic presentation with a
well-flexed head, the largest
transverse diameter of the fetal
head is the biparietal diameter (9.5
cm)
ENGAGEMENT

73. Engagement can be confirmed clinically
by palpation of the presenting part
abdominally and/or vaginally
The head is assumed to be engaged if
the leading edge has reached the ischial
spines and there is no significant
molding or scalp edema

74. Head in Synclitism: the sagittal suture corresponds
to the diameter of engagement with the head enters
the brim
Anterior asynclitism: Anterior parietal presentation
Posterior asynclitism: Posterior parietal presentation
Mild degree of asynclitism are common but severe
degrees indicate cephalopelvic disproportion
PRESENTATION

75. downward passage of the presenting
part through the pelvis
The greatest rate of descent occurs during the
deceleration phase of the first stage and during the
second stage of labor
Forces involved:-
1. Pressure of amniotic fluid
2. Pressure of fundus upon breech with contraction
3. Maternal abdominal muscles
4. Extension and straightening of fetal body
DESCENT

76. o Occurs passively as the head
descends
o due to resistance related to the shape of bony pelvis
& by the soft tissues of the pelvic floor
o Although flexion of the fetal head onto the chest is
present to some degree in most fetuses antepartum,
complete flexion usually only occurs during the
course of labor
o A deflexed head presents a larger diameter, which
may be too large to negotiate the pelvic bone
FLEXION

77. o Rotation of the presenting part
from its original position (usually transverse with
regard to the birth canal) to the anteroposterior
position as it
passes through the pelvis
o As with flexion, internal rotation is a passive
movement resulting from the shape of the pelvis
and the resistance of the pelvic floor musculature
INTERNAL ROTATION

78. o Occurs once the fetus has
descended to the level of the
introitus
o This descent brings the base of the occiput into
contact with the inferior margin of the symphysis
pubis
o At this point, the birth canal curves upwards
o The fetal head is delivered by extension and
rotates around the symphysis pubis
EXTENSION

79. o After the fetal head deflexes (extends),
it rotates to the correct anatomic
position in relation to the fetal torso;
left or right rotation depends on the
orientation of the fetus
o Passive movement resulting from a release of the
forces exerted on the fetal head by the maternal bony
pelvis and its musculature and mediated by the basal
tone of the fetal musculature
EXTERNAL ROTATION

80. Exercise :-
1. Define management of 3rd stage of labor?
2. Write I st stage of labor?
3. Define Fetal head movement in normal delivery?
4. Define moulding ?
5. Define fetal skull ?
6. Difference between true and false labor ?

81. MECHANISMOFLABOUR

82. DEFINITION
Series of events that takes place on genital organ in
an effort to expel the viable product of conception out
of the womb through vagina into the outerworld.

83. PRINCIPLES:-
There are three principles of mechanism of
labour.
a) Descenttakesplace throughout labour.
b) Whichever part leads and first meets the
pelvic floor will rotate forward until it comes
under symphysispubis.
c) Whatever part emerges from the pelvis will
pivot around pubicbone.
Nemonics DSP (descent, symphysis pubis and
pubic bone) to remember principles of
mechanism of labour.

84. CRITERIAFORNORMAL
MECHANISMOFLABOUR
• Lie is longitudinal
• Presentation cephalic
• Position ROAor LOA
• Attitude is good flexion
• Denominator is occiput
• Presenting part is posterior part of anterior
parietal bone

85. PRINCIPLEMOVEMENTSIN
NORMAL MECHANISMOF
LABOUR
• Engagement
• Descent
• Flexion
• Internal rotation ofhead
• Crowning
• Extension of head
• Restitution

86. PRINCIPLEMOVEMENTSIN
NORMAL MECHANISMOF
LABOUR
• Internal rotation of shoulders
• External rotation of head
• Delivery of body by lateral flexion
Nemonics to remember mechanism of labour
END FLICERICED (flicer meansvery bright ) soflicer
company ke end hone seuskamanaager iced ho gya.

87. PRINCIPLEMOVEMENTSIN
NORMAL MECHANISMOF
LABOUR
• Engagement
– Engages with sagittal sutures in right oblique and
biparietal diameter in leftoblique
– Occiput points to left ileo pectineal eminence
• Descent
– Fetus descent due to contraction and retraction of
uterine muscle
• Flexion
– Engaging diameter is suboccipito frontal (10cm)
– Changesto suboccipito bragmatic (9.5cm)

88. Engagement

89. • Internal rotationofhead
– Occiput is the leading part
– Rotatesone by eighth of the circle
– Sagittal suture comesin APD
– Slight twist in the neck of thefetus
• Crowning
– Biparietal diameter stretches at vulval outlet
• Extensionof head
– ReleasesSinciput face andchin
– Head is born by flexion
• Restitution
– Twist in theneck of the fetus is corrected by slight untwisting
movement
– Occiput turns one by eighth of the circle towards the maternal
side

90. Crowning

93. • Internal rotation of shoulders
–Shoulders rotate one by eighth of acircle to lie
under symphysis pubis
• Externalrotation of head
–Occiput rotates further one by eighth to the
mothers left side
• Delivery of body bylateral flexion
–Anterior shoulder escapesunder symphysis pubis
–Posterior shoulder sweepsthe perineum
–Bodyis born by lateral flexion