The Third Stage of Labour Flashcards
NICE defines the 3rd stage of labour as the time from ? to ?
from the birth of baby to expulsion of placenta and membranes
by the beginning of the 3rd stage, the placental site has reduced in size by ?
75%
what are the 3 phases in the separation and expulsion of the placenta?
latent: uterus is contracting and retracting but placenta hasn’t yet sheared off
detachment: contraction and retraction continues, uterine wall thickens
expulsion: placenta fully away from uterine site, uterine wall much thicker, retroplacenta clot
the retroplacental clot:
aids in separation
formed by blood seeping between the septa of the spongy layer of the uterus and the placental surface
(blood comes from vessels becoming congesting and bursting after compression of placenta)
retraction of oblique muscle fibres form ?
living ligatures
living ligatures constrict blood vessels so…
blood does not drain back into the maternal system
what are the 2 methods that a placenta separates from the maternal wall?
schultze method
matthew duncan method
the schultze method of placental seperation:
separatation starts in the centre of the placenta and this descends first
retroplacental clot forms
fetal surface appears first at vulva and membranes trail behind
associated with less blood loss (quicker separation)
how common is the schultze method of placental separation?
occurs in 80% of cases
matthew duncan method of placental separation:
separation begins at lower edge of placenta
placenta slips down sidewards and materal surface appears first at vulva
associated with longer duration, increased blood loss and ragged membranes
how common is the matthew duncan method of placental separation?
occurs in 20% of cases
what is the average blood flow through the placental site?
500-800ml per minute
what are the 4 vital mechanisms that control bleeding after placental expulsion?
empty uterus fully contracts and walls close in (apposition)
myometrium continues to contract and forms ‘living ligatures’
blood clotting begins at site of placental attachment and becomes covered with fibrin mesh
skin to skin will increase oxytocin levels (further contraction of uterus)
what percent of the fibrin mesh that covers the placenta is fibrinogen?
10%
what are the 2 main approaches to the third stage of labour?
physiological
active management
the physiological third stage of labour involves a package of care including…
no routine use of uterotonic drugs
no clamping of cord until pulsation has stopped
delivery of placenta by maternal effort
the active management of the third stage of labour involves a package of care including…
routine use of uterotonic drugs
optimal clamping and cutting of cord
controlled cord traction after signs of separation
when a woman is wanting a physiological first stage of labour it is important to…
keep her in a upright position (e.g. over bag in toilet)
encourage woman to empty bladder
put baby to breast (oxytocin producing environment)
when a woman is wanting a physiological first stage of labour it is important NOT to…
administer an oxytocic (unless heavy bleeding)
palpate uterus (‘fundus fiddling’ - causes spasms)
touch cord or apply cord traction
clamp cord
the first stage in the active management of the 3rd stage of labour:
give a prophylactic uterotonic after birth or birth of anterior shoulder
what are the 2 most common prophylactic uterotonic drugs given?
syntocinon - oxytocin (given IM)
syntometrine - oxytocin and ergometrine (given IM), can cause vomiting and hypertension but lasts a lot longer
the second stage in the active management of the 3rd stage of labour:
optimal cord clamping:
cord should not be clamped or cut until more than a minute has passed from birth
expands neonatal blood volume by 20-50% (decreases anaemia)
reduces the chances of a sudden drop in neonatal blood pressure
the third stage in the active management of the 3rd stage of labour:
CCT/controlled cord traction:
woman should be in sitting/semi-recumbent position and signs of separation are observed (fresh blood loss)
dominant hand to apply downward traction until placenta visible
non-dominant hand pushing uterus upwards ‘guarding’
once visible, upward traction to follow curve of carus
lotus birth:
birthing both baby and placenta and keeping them attached until cord falls off on its own
this can take 3 to 10 days
a prolonged third stage of labour would be diagnosed if…
not completed within 30 minutes with active management
not completed with 60 minutes with physiological management
(NICE guidelines)
it is estimated separation of the placenta occurs within…
3 minutes
midwives examine placenta to check it is complete:
circle type shape
iron/blood odour
bright red and patches of dark red in colour, shouldn’t be signs of calcification
maternal side: retroplacental clot, shouldn’t be cotyledons missing
fetal side: 2 membranes and 3 vessels in cord (AVA), centrally inserted cord
average length of umbilical cord:
50-60cms
succenturiate lobe:
abnormality in placenta
occurs in 1.7% of pregnancies
two sites attached to uterus (increases chance of not coming away, increased blood loss and chances of infection)
more common as maternal age increases and IVF pregnancies
bipartite placenta:
abnormality
placenta separated in two but joined by vessels in between
very rare
high risk of increased blood loss
velamentous umbilical cord insertion:
abnormality
cord inserted in edge of the placenta
fetal blood vessels unprotected and exposed
risk of fetal blood loss due to chances of damage to vessels
can be picked up on scan
