Mechanism of Labour and stages of labour

Mechanism of Labour and stages of labour

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  PRESENTED BY MR KALYANKUMARMSC(N) Mechanism of Labour
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  Definition  Series ofevents that occur on the head and the fetal trunk in the process of adaptation, during its journey through the pelvis.
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  Mechanism of labour Engagementof head Flexion of head Internal rotation of head Crowing Extension and birth of head Restitution Internal rotation of shoulders & external rotation of head Birth of shoulders & trunk by lateral flexion (Descenttakesplacethroughoutbirthingprocess)
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  First stage oflabour  It starts from onset of labour pains to the full dilatation of the cervix. Latent phase:  Cervix dilated to 0-3 cm  Mild and short contractions Active phase: Moderate to strong contractions  Cervix dilates to 4-7 cm  Bloody show  Membranes may rupture
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  Transition phase: Strongcontractions  Cervix dilates 7-10 cm  Increased bloody show  Irritable, restless, emotional  Leg tremors, sudden nausea and vomiting. Duration: 12 hours in primigravida  6 hours in multigravida.  Duration of labour varies and influenced by :- Parity, psychological state, presentation, position, pelvic shape.
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  Second stage oflabour  It starts from full dilatation of the cervix to the expulsion of fetus from birth canal. Latent phase: May last upto 1 hour  Decrease in frequency and increase in strength of contractions Active phase: Urge to push  Stronger and closer contractions
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  Transition phase: Beginswith fetal head on perineum; perineum bulges.  Leg cramps are common. Duration: Average duration is around one hour in primigravida and 30 minutes in multigravida.
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  Third stage oflabour  In this stage, the separation and expulsion of placenta takes place.  After delivery some women have shivering, after short interval discomfort in the lower abdomen reappears due to uterine contractions  Before separation of placenta, fundal height reaches below the umbilicus and the uterus becomes discoid in shape  After separation, placenta comes down into lower uterine segment The signs of placental separation are:  Sudden gush of blood  The length of the umbilical cord increases Duration: Average duration is 5-15 minutes.
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  Fourth stage  Thisis from expulsion of placenta until 2 hours after the birth.  This is an important period and requires close observation of the mother. The mother is kept in the delivery room for 1 hour. She is checked for bleeding, blood pressure and pulse .
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  Summary Conclusion