What are the three stages of labour?
1st - onset of regular contractions to full dilatation of the cervix
2nd - from full dilation of the cervix to the birth of the baby
3rd - birth of the baby to delivery of the placenta and membranes, and control of associated bleeding
Presentation of the foetus
Part of the foetus which lies at the pelvic brim or lower pole of the uterus
What are the five common presentations of the foetus?
Breech (more common in preterm)
Brow (head is de-flexed)
Face (complete extension of the head)
Shoulder (twins, placenta praevia)
Induction of labour
Process of artificially starting labour.
Has an impact on the birth experiece of women. May be less efficient and usually more painful than spontaneous labour. Epidural and analgesia more likely to be required.
In what situations may induced labour be indicated?
Maternal compromise (pre-eclampsia)
Poor obstetic history
Prematue rupture of membranes with no contractions.
When the foetus and/or mother will benefit from a healthier outcome than if the birth is delayed. Only considered when vaginal delivery is appropriate
What are the main methods of induction?
Prostglandins given vaginally
Artifical rupture of membranes
What are the three cephalic presentations in labour?
How can the state of the foetus be monitored in labour?
Foetal heart rate (should be increasing)
Presence of meconium (indicated distress)
What are the two main types of foetal monitoring?
Intermittent foetal monitoring
Continuous foetal monitoring
What is the normal foetal heart rate?
What is the normal colour of liquor?
straw-coloured and clear
What interventions to facilitate birth?
Environment (dim lighting)
Factors which increase risk of pelvic floor dysfunction
obstetric risks ( lacerations etc),
Events of the first stage of labour
Increased prostaglandin release stimulates and an increase in oxytocin, producing more forceful contractions.
As contractions increase the stretch receptors in the cervix send fibres to the hypothalamus and increases OT. Makes contractions more foreceful and frequent (Ferguson reflex)
Muscle fibres shorten but do not relax fully, the fundus shortens.
This pushes the presenting part of the foetus towards the birth canal and dilates the cervix.
Stage ends when cervix is 10cm
Events of the 2nd stage of labour
The descending head flexes as it meets the pelvic floow reducing the diameter of presentation.
There is then internal rotation to bring the shoulders through the bones of the pelvis.
The flexed head descends through the vulva, stretching the vagina and perineum and the head is delivered. Risk of tearing may be reduced by an episiotomy
The shoulders then rotate are delivered, rapidly followed by the rest of the foetus.
Stage ends when the baby is fully delivered.
Events of the third stage of labour
Following delivery of the baby there is powerful uterine contractions, which separate the placenta and it moves to the upper part of the vagina/lowe uterus.
Placenta and membanes are also expelled within 10-20mins.
Contraction of the uterus compresses spiral arteries and endometrial vessels to reduce bleeding. Process can be enhanced by administering oxytoxin.
Completes third stage of labour.