Stages of Labour Flashcards
what happens before labour starts?
Braxton hicks contractions
plug of mucous and blood falls out (bloody show) and/or amniotic sac ruptures (waters breaking) - triggers onset of true labour contractions
what happens in true labour contractions
pull on thick tissue of the cervix causing it to efface (get thinner) and dilate to allow foetus to exit via cervix
originate in pacemaker of tubal ostia in uterus
synchronised waves spread downwards from ostia
become more intense and get longer as they progress
normal foetal position at onset of labour?
longitudinal
cephalic presentation
occipito-anterior
flexed head
change in ration of which hormones trigger labour?
oestrogen:progesterone
more oestrogen
how is oestrogen involved in labour?
contracts the uterus
promotes prostaglandin production
facilitates gap junction formation in myometrium
how is progesterone involved in labour?
keeps uterus settles
prevents gap junction formation in myometrium
hinders contractions
what other things help initiate labour?
fergusons reflex
increase in oxytocin receptors
secretion of surfactant and foetal cortisol by foetus
increase in hyaluronic acid
what is fergusons reflex?
neuroendocrine reflex where pressure exerted on cervix and vaginal walls sustains uterine contractions
effect of oxytocin on labour?
initiates and sustains uterine contractions
acts on decidual tissue to promote prostaglandin release, phospholipiase C activity and increase in cytosolic calcium promoting uterine contractility
effects of surfactant on labour?
stimulates prostaglandin synthesis
effects of cortisol on labour?
stimulates increase in maternal oestrogen
effects of hyaluronic acid?
decreases firmness of cervix
latent phase of stage 1 labour?
can last a few days
beginning > 3/4cm dilated
mild irregular contractions
shortening and softening of cervix
active phase of stage 1 labour?
4>10cm dilation (full dilation)
contractions become rhythmic and stronger
slow descent of the presenting part of the foetus
what happens in stage 2 of labour?
delivery of baby
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what are the 7 cardinal movements of labour?
engagement (3/5 head entered pelvis) descent flexion internal rotation crowning and extension external rotation expulsion
normal discharge following delivery?
1st = lochia (blood mucous and endometrial castings)
rubra (fresh red blood) = for 3-4 days
serosa (brown-red, watery) = 4-14 days
alba (yellow discharge) = 10-20 days
shouldn’t have blood following delivery after how many days?
14 days
normal blood loss in labour?
<500ml
what stops bleeding after delivery?
hypercoagulable state in pregnancy
contractions strangulate pregnancy
myo-tamponade opposition of anterior/posterior walls
how does the body change in puerperium?
fundal height reduces to normal within 2 weeks
weight of uterus drops from 1000g to 50-100g
endometrium regenerates by end of week 1 (but not at placental site)
physiological diuresis commences week 2-3 post natal
