Labour Flashcards
Define labour. (2)
The process whereby the fetus and placenta are expelled from the uterus, which normally occurs during weeks 37-42.
How is labour diagnosed? (2)
Painful uterine contractions are accompanied by dilatation and effacement of the cervix
What are the three stages of labour. (3)
1: Initiation to full cervical dilatation
2: Full cervical dilatation to delivery of the fetus
3: Delivery of fetus to delivery of placenta
What are the three mechanical factors that determine progress through labour? (3)
Power
Passage- dimensions of pelvis and resistance of soft tissues
Passenger- dimensions of fetal head
What bony prominences are used to measure the degree of fetal decent? (1)
Ischial spines
What is the ideal presentation of the fetus at birth? (1)
Flexed vertex presentation
extension of various degrees causes increased presenting diameter
How does the fetus rotate during the second stage of labour? (6)
Engagement in occipito-transverse (OT) Descent and flexion Rotation 90' to OA Descent Extension to deliver Restitution and delivery of shoulders
(in 5% it rotates to occipital-posterior and increased difficulty of delivery)
With regards to describing the fetal head, what does presentation and presenting part mean? (2)
Presentation: part of fetus that occupies the lower segment or pelvis.
Presenting part: lowest part of the fetus palpable on vaginal examination. e.g. vertex, brow, face.
What does the position and attitude of the head describe/ (2)
Position: describes the rotation. OT, OA or OP
Attitude: describes the degree of flexion.
What is effacement of the cervix? (2)
Normally tubular cervix is pulled up into the lower segment until it is flat. Commonly associated with bloody show.
Name the 2 phases of the first stage of labour. (2)
Latent (first 3 cm)
Active: 1cm/hour in nulliparous, 2cm/hour in multiparous
Define slow labour and prolonged labour. (2)
Slow labour: after latent phase, progress less than 1cm/hr
Prolonged labour: after latent phase >12 hours duration
Name 3 causes of slow progress in labour. (3)
Power: inefficient uterine action
Passenger: fetal size, disorder of rotation, disorder of flexion
Passage: cephalo-pelvic disproportion, rarely cervical resistance
How is slow progressing labour managed? (3)
Generally: can wait if desired, mobilise
Nulliparous: amniotomy, oxytocin
Multiparous: amniotomy, oxytocin if malpresentation excluded
If fails: C/S in first stage or instrumental delivery if second stage.
What is Bishop’s score? (1)
Pre-labour scoring tool to help determine whether induction of about will be required.
Name 2 methods of inducing labour. (2)
Vaginal PGE2.
Amniotomy (artificial rupture of membranes)
Oxytocin after SROM or ARM.
(Cervical sweeping of membranes)