Normal labour** Flashcards
during labour there is an interplay of which three factors
power - uterine contraction
passage - maternal pelvis
passenger - fetus
progesterone does what
what happens to the levels in labour
keeps the uterus settles and prevents formation of gap junctions and hinders contractibility of myocytes
goes down
oestrogen in labour
makes the uterus onctract
promotes prostaglandin production which produces more oestrogen
what does oxytocin do in labour
where is it synthesised
what happens to the number of oxytocin receptors
initiates and sustains contractions
acts on decidual tissue to promote prostaglandin release
directly in decidual and extra embryonic metal tissues and in the placenta
increase in myometrial and decidual tissue near the end of the pregnancy
how is labour initiated
change in oestrogen/progesterone ratio
fetal adrenals and pit hormones may control timing of onset of labour
myometrial stretch due to uterus getting bigger leads to excitability of myometrial fibres
mechanical stretch of cervix and stripping of metal membranes
fergusons reflex - increase oestrogen and increased prostaglandin release
other causes that lead to labour
pulmonary surfactant secreted into amniotic fluid stimulates prostaglandin synthesis
increase in production metal cortisol stimulates an increase in maternal estriol
increase in my-metrical oxytocin receptors and their activation results in phospholipase C activity and subsequent increase in cytosolitic calcium and uterine contraction
3 stages of labour consist of what
first - latent/active
second - cervix dilated to 10cm - delivery of baby
third stage - delivery of placenta and membranes
latent stage
mild irregular uterine contractions, cervix shortens and softens, duration variable
active phase
4cm on to full dilatation
slow descent of the presenting part
contractions progressively becomes more rhythmic and stronger
second stage of the labour starts with what
how long does it take
what can happen in low risk px
starts with complete dilatation of the cervix (approx 10cm)
in nulliparous women considered prolonged if it exceeds 3 hours with regional analgesia or 2 hour without
in multiparous women - consider prolonged if it exceeds 2 hours with analgesia or 1 without
in low risk vaginal examinations are not always carried out to assess time for full dilatation
what happens during the third stage of labour
time
management actions taken
delivery of the baby to expulsion of the placenta and fatal membranes
av duration 10 mins can be 3 min longer
spontaneous delivery of the placenta - be prepared
use of oxytocin drugs and controlled cord traction is preferred for lowering risk of post partum haemorrhage
active management of third stage
syntometrine 1ml ampoule given
or
oxytocin 10 units
cord clamping and cutting
controlled cord traction
bladder emptying
cervical softening
increase in hyaluronic acid gives increase in molecules among collagen fibres
decrease in bridging among collagen fibres gives decrease in firmness of cervix
cervical ripening
decrease in collagen fibre alignment
decrease in collagen fibre strength
decrease in tensile strength of the cervical matrix
increase in cervical decorin
braxton hicks contraction what
when do they start/are felt
tightening of the uterine muscles - thought to aid the body to help prepare for birth
can start 6 weeks into the pregnancy
not usually felt until second or third trimester
irregular, do not increase in frequency or intensity
resolve with ambulation or change in activity
relatively painless
true labour contractions feelings
when
like a wave
pain starts low, rises until a peak and then ebbs away
if you touch the mothers abdomen during one it feels hard
start about 5 mins apart
what causes true labour contractions
pain
oxytocin causes uterus to contract
evenly spaced
get more intense and painful over time
tighten the top part of the uterus pushing the baby down
what do both kinds of contractions do to the cervix
promote thinning of the cervix
where is the pacemaker and what direction does the wave spread
how do the waves synchronise
polarity
normal contractions have what
region of tubal ostia, downward direction
both ostia
upper segment contracts and retracts, lower segment and cervix stretch, dilate and relax
fundal dominance with a regular pattern and an adequate resting tone
best type of pelvis t have
gynaecoid pelvis
anthropoid pelvis
oval shaped inlet with large AP dm and smaller transverse dm
android pelvis
who are more at risk of this type of pelvis
triangular or heart shaped inlet and is narrower from the front
african caribbean women
what does liquor do
nurtures and protects fetus and facilities movement
when does the membrane usually rupture
in the first stage
