second stage of labour Flashcards
give a definition of the second stage of labour
the period of full dilation of the cervix to the expulsion/birth
what happens between the 1 and 2 stage
physiological changes occur- transitional changes
are there any signs to signify the changing of stages
no clear signs, bunch of signs togerther may notify this waters breaking, dilation +gaping of anus anal cleft# Rhomboid of michaelis
what is the appearance of the presenting part
conclusive sign of 2 stage
Exsessive moulding ad caput succedabeum formation may protrude through cervix before full dilation
often seen as bleeding due to separation of Plecenta
how many stages dose the 2 stage of labour have
2
Latent and active
what happens in the latent phase of the 2 stage
begins at full dilation, presenting part may be visible,
head begins to descend due to force of contractions and stretching of the tissue,
what happens in the active phase
once the head is visable, pressure reterns to normal, causes reflex stimuli for maternal explsion pushing what starts the active phase
what is maternal pushing a sign of
active phase
what are the 3 main process involved in the second stage
1-contractions
2- secondary powers- the passenger (pelvis)
3- fetal axis pressure- passenger- fetus
what happens to contractions at the end of the 1st stage
often lull before they become expulsive in nature
what are contractions like in the 2 stage
become longer and stronger but may be less frequent so that the woman and her baby can recover between each expulsive effort
what are secondary powers
in active phase- pressure causes pushing reflex, fetus is compacted in contractions, spontaneous pushing is best
what dose fetal axis pressure cause
diplacment of soft tissue in pevis
bladder push up
fecal matter can be released due to rectum flatterned
levator ani muscles of the pelvic floor thin out and are displaced laterally
perineal body is stretched and thinned
what causes fetal axis pressure
the fetus descending the birth canal
can the fetal axis pressure help the baby
can aid descent
increased flexion of the head which results in smaller presenting diameters, more rapid progress and less trauma to the mother and fetus.
what can aid in fetal axis pressure
optimized by upright positions- mother standing/sitting up straight
what issue can stop the mechnisms of labour
curve of birth canal, large size baby head can also be an issue
what is the mechanism of labour
movments of the fetus to move through the birth canal
what are the Common mechanisms for normal labour
The lie is longitudinal.
• The attitude is one of good flexion.
• The presentation is cephalic.
• The position is right or left occipitoanterior.
• The denominator is the occiput.
• The presenting part is the posterior part of the anterior parietal bone
what are the movments involved in mechanism of labour
Descent. • Flexion. • Internal rotation of the head. • Crowning and extension of the head. • Restitution. • Internal rotation of the shoulders and external rotation of the head. • Lateral flexion.
what is the Anterior fontanelle
: A diamond shaped structure connecting 4 sutures. 2.5cm across 3cm long
on the top of the head near the front
what is the Posterior fontanelle
triangular in shape.
Presents when head well flexed
near the back of the head
what is the Bi parietal diameter
Widest part of fetal skull. Crowning occurs when this is delivered
what influences the degree of flexion or extension of the head
The presentation and position of the fetal head in relation to the pelvic brim
where is the Submentobregmatic measured to and from
Measured from the junction of the chin with the neck to the centre of the anterior fontanelle
when dose the Submentobregmatic measurement engage
This diameter engages when the head is fully engaged in a face presentation
where is the Suboccipitobregmatic measures to and from
Measured with the junction of the head with the neck to the centre of the anterior fontanelle
when dose the Suboccipitobregmatic engage
Presents when the fetal head is flexed. Optimum diameter for labour
May result in normal moulding / caput
when dose the Occipitomental
present
Presents in a brow presentation where the head is part flexed
when dose the Occipitofrontal present
Presents when ther is insufficient flexion of the head.
Results in persistent OP / face to pubes.
can fetus brains flex
Yes they can flex. it is called moulding
what is the advantage of flex in a feteus head
adapting to prolonged compression in order to enhance passage through the birth canal
by who much can the fetus head flex/mould
Moulding can increase /decrease diameters of head by up to 1.5cm
changes shape but not volume
how can the fetus head mould/flex
the frontal bones move under the anterior aspects of the parietal bones and the occiput moves under the parietal bones at the back
when and why dose desent occur
may have occurred in the antenatal period, so that the head is engaged-
sagittal suture is in the transverse diameter of the pelvis
when is descent speeded up
continued descent during the first stage of labour and this is speeded up by maternal effort during the 2nd stage of labour
what determines which diameter will present in labour
The attitude (flextion)determines this
what occurs to the flextion of a babies head in labour
increases in labour, due to Pressure transmitted from the fundus of the uterus down the fetal spine
why dose crowning occur
this occurs when the head is visable and is no longer affected by contractions. it pivots on the suboccipital region around the pubic bone
what is Restitution
movement made by the head following delivery which brings it into correct alignment with the shoulders
how do the shoulders rotate
anterior shoulder is the first to reach the pelvic floor and this now rotates forward to lie under the symphysis pubis. This movement is accompanied by external rotation of the head
what happens when the internal shoulders rotate
The occiput now lies laterally, turned towards the woman’s thigh
what occurs in Lateral flexion
the spine bends laterally on its way through the curved birth canal, once the shoulders are out
name three Malpresentations of the fetal head
Primary face presentation
secondary face presentations
Brow presentation
what is face presentations
Occurs when the head and neck are hyperextended but limbs flexed so baby lying in an S shape.
Presenting part is therefore the chin
when dose primary F presentation occur and what are the causes
occurs before labour and has recognised causative factors:
Anencephaly – no vertex to present
Tumours of fetal neck preventing flexion
Excessive tone in fetal extensor muscles
when dose secondary F presentation occur and its causes
develop in labour: Deflexed OP position Uterus laxity Flat pelvis Prematurity Polyhydramnios Multiple pregnancy
what position must the chin be in to be delivery vaginally
Chin must be anterior to deliver vaginally
when dose Brow presentation occur and its causes
The least common presentation
Head is midway between flexion and extension.
Causes: cephalopelvic disproportion
fetal prematurity
increasing parity
C-section often used in this presentation
in which presentation is C-section often used
Brow presentation
in what stage is the placenta and it’s membranes expelled
3 stage
name two approached to labour management in the third stage
active and physilogical
what is active management
administer drugs clamp and cut umblical cord brace utrus controlled cord traction to expedite delivery of the placenta and membranes
what is physiological management of the third stage
No drugs
no cord clamping, until p is delivered
no cord traction
what are some signs of the third stage
gush of blood
cord lengthening
globular+ firm utrus, uturs rises
when should the third stage occur
30 mins after delivery of baby
what is a lotus birth
parents carry around placenta still connected to baby until it naturally falls off
what is the risk of a lotus birth
Risks of infection remain for the baby
what is Placentophagy
eating the plecenta- made into pills
