1st Stage of Labour Flashcards
What are the stages and phases of labour?
Latent phase
Active 1st stage
Rest and thankful phase
Active 2nd stage
3rd stage
4th stage
When does oxytocin flow best according to Nolan 2020?
When women feel safe, when privacy is guranteed and when they are unobserved
When and where is oxytocin released from in labour?
Released from the posterior pituitary lobe into the circulation
Released in pulses with increasing frequency and amplitude in the first and second stages of labour
A few pulses released in the third stage of labour
During labour, the fetus exerts pressure on the cervix of the uterus, which activates a feedforward reflex, which releases oxytocin.
What is the problem with Friedman’s work (Friedman’s trajectory)
Friedman was an American obstetrician in the 1950s. His research all took place on white women (middle class, similar ages, supine position), where he tried to find out the labour trajectory. He plotted it on a graph (Friedman’s curve) which estimated the length of each stage of labour.
What do the NICE guidelines describe can be descriptions of the 1st stage of labour
there are contractions and
there is some cervical change, includin cervical position, consistency, effacement and dilation up to 4cm.
What happens to the endocrine in the onset of labour?
Progesterone withdrawal
What happens to the immune in the onset of labour?
Leukocyte and leukotriene activation
What happens in terms of mechanical factors in the onset of labour?
Enhanced uterine stretching and amnio-chorionic membrane disruption.
What do the endocrine, immune and mechanical factors cause in the onset of labour?
An inflammatory activation and protaglandin production to transform the myometrium to an active contractile state at term.
What does progesterone activate?
Prostaglandins which aids the mechanical process
What does activated leukocytes cause?
Inflammatory response aiding the mechanical process.
How does labour start in terms of progesterone withdrawal?
The mechanisms that supress progesterone’s function near term to allow labour an delivery are still shrouded in uncertainty.
A hypothetic scheme of the mechanisms that control progesterone reposnsiveness in teh pregnant human myometrium
What do the placental oestrogens, relaxin and prostogalndins do? (Fuchs et al 1991)
Soften the collagen fibres in the cervix and make it more distensible
How is uterine tissue prepared for labour?
Under the influence of oestrogen, prostoglandins and distension of uterine tissue, uterine tissue is prepared for labour through cell multiplication and hypertropjy (increase in size of cells)
What helps stimulate contractions?
Uterotrophins, including oxytocin, raise levels of intracellular calcium
What else is oxytocin secreted by that is a major contributor to inc oxytocin levels in uterine tissue
fetus
Due to the influence of oestrogens, what does the number of gap junctions in the muscles increasing cause?
Allows inccreased coordination of myometrial contractility