Introduction to normal labour and stages of labour

1. Normal labor
Presented By
Heera KC
MSc. Nursing 2nd year
Maternal Health Nursing
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2. Objectives
• Define labour, normal and abnormal labor.
• Explain the factors affecting normal labour.
• Explain the premonitory signs of labor.
• Distinguish the difference between true and false labour
• State the causes of onset of normal labour.
• Identify the stages of labour.
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3. Labor
• “Labour is the physiological process by which fetus, placenta
and membranes are expelled through the birth canal after
viability (22nd week of pregnancy).”
WHO
• Series of events that take place in the genital organs in an
effort to expel the viable product of conception out of the
womb through the vagina into the outer world is called labor.
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4. Labor may be
• Spontaneous or induced
• Term or preterm
Preterm labor – Prior to 37 weeks
Term – 37 to 42 weeks
Post term – After 42 weeks
Post dates – After 40 weeks
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5. Terminologies
• Parturiant : is a patient in labor and
• Parturition : is the process of giving birth.
• Delivery: is expulsion of the viable fetus out of the womb/ uterus. It is
not synonymous with labor; delivery can take place without labor as
in elective caesarean section. Delivery may be vaginal, either
spontaneous or aided or it may be abdominal.
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6. NORMAL LABOR (EUTOCIA)
• Physiological
process by
which the
fetus, placenta
and membrane
are expelled
through birth
canal after full
term of of
pregnancy.
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7. Criteria of Normal Labour
• Spontaneous in onset and at term.
• With vertex presentation.
• Without undue prolongation.
• Natural termination with minimal aids.
• Without having any complication affecting the health of the mother
and or the baby.
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8. Factors affecting normal labour
Psychological response
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Passage
Power
Passenger
Position

9. Power
Primary power: Involuntary
uterine contraction
• Responsible for effacement
and dilation of cervix
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Secondary powers
Contraction changes to
expulsive.
Voluntary bearing down
of mothers.
No efforts in cervical
dilation.
Primary and secondary force to expel fetus.

10. Passage
• Soft tissue passage: change in uterus, cervix, vagina , pelvic floor
• Bony Passage: true pelvis, outlet
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11. Passanger
• Fetus, placenta, membrane, liquor amnii, cord.
• The passage of fetus is determined by various factors: the size of the
fetal head, fetal presentation, fetal lie, fetal attitude
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12. Position of a labouring women
• Frequent change in position relief fatigue, increase comfort and
improve circulation.
• An upright position (walking, sitting, kneeling or squatting offers a
number of advantage.
• If women wishes to lie down left lateral position is suggested.
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13. Abnormal Labour (Dystocia)
• Any deviation from the normal labour is called abnormal labour.
• Fetal presentation other than vertex or having some complications
even with vertex presentation affecting the course of labour or
modifying the nature of termination or adversely affecting the
maternal and fetal prognosis is called an abnormal labour.
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14. Signs and symptoms of onset of spontaneous normal
labor
• Lightening
• Cervical changes
• Appearance of false pain
• Taking up of the cervix
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15. Lightening
• This is sinking of the presenting part into the true pelvis, which takes
about 2-3 weeks before onset of labor in primigravida and during
onset of labor in multigravida.
• It is due to the active pulling up of the lower pole of the uterus around
the presenting part.
• It signifies incorporation of the lower uterine segment into wall of the
uterus, it may be gradual process or may be felt abruptly.
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16. Lightening
• This diminishes the fundal height and hence minimizes the pressure on
the diaphragm.
• The mother experiences a sense of relief from the mechanical
cardiorespiratory problems.
• Breathing is easier, the heart and the stomach can function better and
the relief experienced by the women is described as lightening.
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17. Showing phenomenon of “lightening”.
(A) Before and (B) after lightening
(A)
(B)

18. CERVICAL CHANGES
• A ripe cervix is
(a) soft,
(b) 80% effaced (<1.5 cm
in length),
(c) admits one finger
easily, and
(d) cervical canal is
dilatable.
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19. APPEARANCE OF
FALSE PAIN
• Erectile and irregular
pain, causing the
uterus to contract and
relax, where as in the
labor the uterus
contract and retracts
regularly.
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TAKING UP OF
THE CERVIX
Taking up of the cervix occurs
because it is being and
merged into the lower uterine
segment.

20. Taking up of the
cervix

21. False labour pain (spurious labour)
• Period of irregular (but sometimes) regular contractions that occur
without progressive cervical dilation.
• Contractions usually do not progress in their frequency, duration or
intensity.
• Usually appears prior to the onset of true labor pain by one or two
weeks in primigravida and by few days in multipara.
• Found more in primigravida than multigravida women.
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22. Characteristics
• Dull in nature and usually confined to the lower abdomen and groin.
• Continuous and unrelated with hardening of the uterus.
• Without any effect on dilatation of the cervix.
• Pain relives by use of sedatives and position changes.
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23. True labour pain
• Onset of regular uterine contractions (pain) that become more frequent
and forceful in later weeks of pregnancy characterized by:
1. Painful uterine contractions with regular interval and increasing
intensity (labour pain)
2. Appearance of show
3. Progressive effacement and dilatation of the cervix.
4. Formation of the ‘bags of waters’
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24. Appearance of show Dilatation of
internal os

25. Formation of bag of water

26. S.no Features True labour False labour
1 Painful uterine contraction Regular Irregular
2 Interval between pain Gradually
shortens
Remains long
3 Intensity Increases Same
4 Site of pain Back and
abdomen
Chiefly lower abdomen
5 Cervical dilatation and effacement Present Absent
6 Bulging of fore water Present Absent
7 Sedation and enema Pain not stopped Usually relieved
8 Show Usually present Absent
Difference between false and true labour

27. THEORIES AND CAUSES OF ONSET OF LABOR
• Mechanical factors
• Hormonal factors (endocrine)
• Neurological factors
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28. ↑ Uterine activity
Mechanical stimulation
Overstretching of the uterus and pressure of
presenting part on the lower segment
Mechanical factors

29. Hormonal factors
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Cascade of
events activates
the fetal
hypothalamic
pituitary
adrenal axis
prior to the
onset of labour.
Feto-placental contribution

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Hormonal factors Cont…

31. Uterine contraction
↑ Production of oestrogen and prostaglandin from placenta
↑ cortisol secretion from fetal adrenal
↑ Fetal adrenal activity
↑ release of adrenocorticotrophic hormone
↑ corticotrophic Releasing hormone
Fetal hypothalamic pituitary adrenal axis stimulated prior onset of labour

32. ESTROGEN
Theory
MODE OF ACTION
Increase
prostaglandin
synthesis
Increase myocardial
contractile protein
Increase excitability of
myometrial cell
membrane
Promotes synthesis of
receptors for oxytocin
in the myometrium
and decidua
Release of oxytocin
from maternal
pituitary
HORMONAL FACTORS Cont…

33. ↑ fetal production of dehydroepiandrosterone sulphate and cortisol
inhibit the conversion of fetal pregnenolone to progesterone
Decrease Progesterone synthesis
Alteration of oestrogen, progesterone ratio
Increase Uterine contraction
HORMONAL FACTORS Cont… Progesterone
During pregnancy, inhibits myometrial contraction, but in late pregnancy

34. Myometrial contractile system
Enhances gap junction, Increase of oxytocin
receptors in decidua
↑ Prostaglandin (from placenta, fetal membranes,
decidual cells and myometrium)
Hormonal theory cont…Prostaglandin

35. Prostaglandin synthesis is triggered by
• Rise In Oestrogn Level,
• Glucocorticoids,
• Mechanical Stretching In
Late Pregnancy,
• Increase In Cyotokines,
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• Infection,
• Vaginal Examination,
• Rupture of the
Membrane.

36. Oxytocin theory
• Oxytocin receptors are present in the uterus; they increase in uterus
with the onset of labour.
• It promotes the release of prostaglandins from the decidua.
• Vaginal examination and amniotomy cause rise in maternal plasma
oxytocin level (Ferguson reflex).
• Oxytocin level reach maximum at the moment of birth.
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38. 3. Neurological factors
• Labor may also be initiated through the nerve pathways.
• α and β adrenergic receptors are present in the myometrium.
• Estrogen acts on the α and progesterone acts on the β .
• The contractile response is initiated through the α receptors of the
postganglionic nerve fibers in and around the cervix and lower part of
the uterus.
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39. STAGES OF LABOR
1. First stage of labour
2. Second stage of labour
3. Third stage of labour
4. Fourth stage of labour
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Cervical dilatation Expulsion after birth

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Expulsion after birth

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after birth

44. Third stage of labour
• Is referred as placental stage.
• It begins after the birth of the baby and ends with the expulsion of
placenta and membrane.
• Uterine contraction decreases basal blood flow, results in thickening
and reduction in the surface area of the myometrium underlying the
placenta with subsequent detachment of the placenta.
• The average time duration is 15-30 minutes, but could be reduced up
to 5 min. by active management of third stage of labour.
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45. Fourth stage of labour
• It is the stage of observation for at least one hour after expulsion of the
placenta and membranes.
• During this period, general condition of the patient and the behavior of
the uterus and bladder are to be observed carefully.
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46. 1st Stage 2nd Stage 3rd Stage 4th Stage
Latent
phase
Active
phase
Transition
al phase
Propulsive
phase
Expulsive
phase
Primi
Total
6-8 hrs 6 hrs 1-2 hrs 1- 2 hrs 15-30
min
1 hr
11-12 hrs
3/4 hr 15-30
min
1 hr
Multi
Total
4 hrs 30min -1
hr
5- 30 min 15-30
min
1 hr
6 ½ hrs 1/4 hrs 15-30 min 1 hr
Duration of labor

47. First stage of labor
• Starts from the onset of true labor pain and ends with full dilation of
cervix.
• Is the longest and most variable stage.
• Also called as cervical stage or dilation stage of labor.
• Its average duration is 11-12 hrs in primigravida and 6-8 hrs in
multigravida.
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48. 3 sub-stages
• Latent phase (early)-: mild intensity and cervix dilates from 0 to 4 cm.
• Active phase:- mild to moderate intensity and cervix dilates from 4 to 7
cm.
• Transitional phase:- moderate to strong intensity and the cervix dilates
from 8 to 10 cm.
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49. Contractions Latent phase Active Phase Transitional
Phase
Frequency 10 – 15 minutes 2 – 5 minutes 2-3 minutes
Duration 15-20 seconds 20-40 seconds more than 40
seconds
Intensity Begin Mild and
become
moderate
Begin moderate
and become
strong
strong
…………………
…
At every 10 minutes interval, assess the
contraction as:

50. (Sign and symptoms) Clinical course of 1st stage of labour
• Painful uterine contraction
• Progressive dilatation and effacement of the cervix.
• Status of the membrane
• Maternal effect
• Fetal effect
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51. PAIN
• Felt more anteriorly with simultaneous hardening of the uterus.
Initially, come at varying intervals of 15–30 minutes with duration of
about 30 seconds.
• But gradually the interval becomes shortened with increasing
intensity and duration.
• In late first stage the contraction comes at intervals of 3–5 minutes and
lasts for about 45 seconds.
• In normal labor, pains are usually felt shortly after the uterine
contractions begin and pass off before complete relaxation of the
uterus.
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52. DILATATION AND EFFACEMENT OF
THE CERVIX
• Cervical dilatation relates with dilatation of the external os.
• Effacement (thinning) is determined by the length of the cervical
canal in the vagina.
• In primigravidae, the cervix may be completely effaced, feeling
like a paper although not dilated enough to admit a fingertip.
• While in multiparae, dilatation and taking up occur simultaneously
which are more abrupt following rupture of the membranes.
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53. DILATATION AND EFFACEMENT OF THE CERVIX
• The anterior lip of the cervix is the last to be effaced.
• The first stage is said to be completed only when the cervix is
completely retracted over the presenting part during contractions.
• Dilatation of the cervix at the rate of 1 cm/h in primigravidae and
1.5 cm in multigravidae beyond 4 cm dilatation (active phase of
labor) is considered satisfactory.
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54. DILATATION AND EFFACEMENT OF THE CERVIX
• Cervical dilatation -
expressed either in terms
of fingers—1, 2, 3 or fully
dilated or in terms of
centimeters (10 cm when
fully dilated).
• It is usually measured with
fingers but recorded in
centimeters.
• One finger equals to 1.5
cm on average.
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Effacement of the cervix is
expressed in terms of
percentage, i.e. 25%, 50%
or 100% (cervix less than
0.25 cm thick).
The term “rim” is used
when the depth of the
cervical tissue surrounding
the os is about 0.5–1 cm

55. STATUS OF THE MEMBRANES
• Usually remain intact until full dilatation of the cervix or sometimes
even beyond in the second stage.
• May rupture any time after the onset of labor but before full dilatation
of cervix- early rupture.
• Premature rupture
• Tensed and bulged in contraction,in between contractions, the
membranes get relaxed and lies in contact with the head
• Acceleration of uterine contractions – when ruptured.
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56. MATERNAL SYSTEM
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Fatigue
Changes in pulse rate
and BP
FETAL EFFECT
During contraction, there may be
slowing of fetal heart rate by 10–20
beats per minute which soon returns
to its normal rate of about 140 per
minute as the intensity of contraction
diminishes.

57. • D.C.,Dutta’s.(2004) Textbook of obstetrics.8th Edition. New central
Book Agency.
• Fraser, DM. , Cooper, MA.(2006) Myles Textbook for Midwives .14th
edition. Churchill Livingstone.
• Roshani,T. ,(2005) Mannual of Midwifery B.3rd Edition. Vidyarthi
Pustak Bhandar.
• Subedi, D., Gautam, S.,(2011) Midwifery Nursing part II. 2nd edition.
Medhavi Publication.
References

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Summary