Normal labour Flashcards
what are the 3 key factors in labour
power - uterine contraction
passage - maternal pelvis
passenger - foetus
role of progesterone before labour
keeps uterus settled - preventing formation of gap junctions in myocytes
role of oestrogen in labour
makes uterus contract by promoting prostaglandin production
role of oxytocin in labour
initiates and sustains contractions
acts on decidual tissue to promote prostaglandin release
where is oxytocin synthesised
decidual and extraembryonic foetal tissues and placenta
factors causing initiation of labour
change in oestrogen/progesterone ratio
foetal hormones
myometrial stretch
ferguson’s reflex
why are multiple pregnancy/larger babies more likely to have pre-term labour
increased myometrial stretch initiating labour earlier
what is ferguson’s reflex
neuroendocrine reflex - positive feedback of uterine contractions from pressure on cervix/vaginal walls
latent phase of labour
up to 4cm
established phase of labour
4-10cm
what is normal progress during established stage of labour
1-2cms/hour
second stage of labour
complete dilation of cervix-delivery of baby
what is prolonged second stage in nulliparous women
> 3 hours if analgesia
>2 hours if not
what is prolonged second stage in multiparous women
> 2 hours with analgesia
>1 hour if not
third stage labour
delivery of baby - expulsion of placenta and foetal membranes
