Definition: Labour is the process by which the foetus is expelled from the uterus. Labour
requires regular, effective contractions that lead to dilatation and effacement of the cervix.
Parturition is the birth process
Delivery is the actual expulsion of the products of conception including the placenta. It is
not synonymous with labour. Delivery can take place without labour as in elective
caesarean section. Delivery can be vaginal or abdominal.
A Parturient is a patient in labour
Labour is divided into: True labour is accompanied by regular uterine contractions
increasing in both frequency and intensity, effacement and dilatation of the cervix and
descent of the presenting part.
False labour: Characterised by irregular brief contractions of the uterus accompanied by
mild back or abdominal pain but lack of progress. The presenting part does not descend.
Normal labour (Eutocia): Fulfils the following criteria: 1. spontaneous in onset and at
term 2. Vertex presentation 3. Not prolonged 4. Natural termination with minimal aids 5.
Without complications affecting the mother or baby
Abnormal Labour (Dystocia): Any deviation from the above definition.
INITIATION OF LABOUR:
Precise mechanism of labour initiation is obscure. Theories include:
Uterine distension: stretching effect of the growing foetus and liquor on the
myometrium can explain labour onset in twins and polyhydramnios. Uterine stretch gap
junction proteins, receptors for oxytocin and specific contraction associated proteins
Foeto-placental contribution: Cascade of events activate foetal hypothalamic-pituitaryadrenal axis.
Prior to labour onset
increased cortisol secretion
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