Normal labour is defined as the spontaneous onset of contractions at term that result in the vaginal delivery of a vertex baby with minimal assistance and no complications. The stages of labour include the first stage of cervical dilation from onset of contractions until full dilation, the second stage from full dilation until delivery of the baby, the third stage until delivery of the placenta, and a fourth stage of observation. The document outlines the criteria for normal labour and abnormalities as well as the causes, stages, and phases within each stage.

1. NORMAL LABOUR

2. DEFINITION
 Series of events that take place in genital organs in an effort to expel the viable
products of conception through vagina is called ‘Labour’

3. Criteria for Normal labour [Eutocia]
 Spontaneous onset at term
 Vertex presentation
 Without undue prolongation
 Natural termination with minimal aid
 No complications
Any deviation from this criteria is ‘Anormal Labour’ or Dystocia’

4. Causes of onset of labour
 Uterine distension
 Fetoplacental contribution
 Estrogen: Release of oxytocin
Promotes synthesis of myometrial receptors for oxytocin
Stimulates synthesis of actomyosin
 Progesterone
 Prostaglandins
 Oxytocin
 Neurological factor

5. Prelabour stage
 Begins 2-3 weeks in primigravidae and few days before in multigravidae before onset
of labour.
 Lightening: 1)Presenting part sinks into true pelvis by active pulling of lower
pole of uterus.
2) Diminishes fundal height and reduces pressure on
diaphragm
3) Frequency of micturition and constipation may increase due
to mechanical factor.
4) It is called ‘Welcome Sign’.
 Cervix becomes ripe, soft and admits a finger easily.
 Appearance of ‘False pain’.

6. TRUE LABOUR PAINS
 Uterine contractions at gradual intervals
which gradually increase in intensity and
duration.
 Associated with ‘Show’ and ‘Bag of
Forewaters’
 Effacement and dilation of cervix
 Not relieved by enema or sedatives
FALSE LABOUR PAINS
 Pains dull in nature and confined to lower
abdomen and groin.
 No ‘Show’ or ‘Bag of Forewaters’
 No effacement and dilation of cervix
 Relieved by enema or sedatives
1)Show: With onset o labour there is profuse cervical secretion and slight bleeding.
Expulsion of cervical mucus plug mixed with blood is called ‘Show’
2) With dilation of cervical canal, the lower pole of fetal membranes become
unsupported and tend to bulge into the cervical canal. As it contains liquor, it is called
‘Bag of Forewaters’.

7. Stages Of Labour
First Stage of Labour
 Begins with onset of True labour pains and ends with full dilation of cervix.
 Average duration:
Primigravidae:12 hours
Multiparae: 6 hours
 Dilation of cervix caused under action of estrogen, progesterone and relaxin. Also
uterine contraction and relaxation help in dilation of cervix.
 Effacement is the process by which the muscular fibres of cervix are pulled
upwards and merge with fibres of lower uterine segment.

9. SECOND STAGE OF LABOUR
 Begins with complete dilation of cervix and ends with the expulsion of foetus.
 Has two phases:
A) Propulsive phase: From full dilation until head touches the pelvic floor.
B) Expulsive: since the time mother has irresistible desire to ‘bear down’ and
push until the baby is delivered.
 Average duration:
Primigravidae: 2hours
Multigravidae: 30 minutes

11. THIRD STAGE OF LABOUR
 Begins with expulsion of fetus and ends with the phase of placental separation, its
descent to lower segment and finally its expulsion with its membranes.
 Average duration is 15 minutes.
 The separation is achieved by marked reduction in the uterine surface area of
placental site following delivery due to retraction.
 There are two ways of placental separation:
1) Schultze – Central
2) Mathews-Duncan – Marginal

12. FOURTH STAGE OF LABOUR
 Observation

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