Normal labour & puerperium Flashcards
definition of labour?
-accompanied by what?
physiological process during which the foetus, membranes, umbilical cord and placenta are expelled from the uterus
-Regular, painful uterine contractions of increasing frequency, intensity and duration Biochemical changes in the cervical tissue allowing cervical effacement & cervical dilatation
Delivery of the fetus and expulsion of the placenta
What are the 3 key factors during labour?
Power: uterine contraction
Passage: maternal pelvis
Passenger: Fetus
Name the hormones involved in labour?
Progesterone
Oestrogen
Oxytocin
Functions of progesterone in labour? (3)
keeps the uterus settled
prevents the formation of gap junctions
hinders the contractibility of myocytes
Functions of oestrogen in labour? (2)
makes he uterus contract
promotes prostaglandin production
Functions of Oxytocin in labour? (2)
- synthesised where?
- change in receptors over pregnancy?
initiates and sustains contractions
acts on decimal tissue to promote prostaglandin release
- in decidual tissue and extra embryonic foetal tissues and in the placenta
- no. of receptors increases myometrial and decimal tissue near the end of pregnancy
What physiological mechanisms initiate labour? (5)
-plus 3 more possible causes
change in oestrogen progesterone ratio
foetal adrenals and pituitary hormones may control the timing of the onset of labour
myometrial stretch increases excitability of myometrial fibres
mechanical stretch of cervix and stripping of foetal membranes
Fergusons reflex
-surfactant secreted into amniotic fluid reported to stimulate prostaglandin synthesis
inc foetal cortisol
inc myometrial oxytocin receptors and their activation results in phospholipase C activity and subsequent increase in cytosolitic Ca and uterine contractility
give the component phases of:
- first stage of labour? (2)
- second stage of labour? (1)
- third stage of labour? (1)
-latent phase up to 3-4cms dilatation
Active stage 4cms-10cms
- full dilatation -> delivery of baby
- delivery of baby -> expulsion of placenta and membranes
First stage of labour
- features of the latent phase? (2)
- features of the active phase? (2)
-mild, irregular uterine contractions, cervix shortens and softens, duration variable
may last a few days
-slow descent of the presenting part
contractions become more rhythmic and stronger
when is the second stage of labour prolonged in:
- nulliparous women
- multiparous women
- 2 features of full dilatation?
- if it exceeds 3 hours with regional anaesthesia and hours without
- if exceeds 2 hours with regional anaesthesia or 1 without
-anal pouting
flattening of the perineum
Third stag of labour:
- normal duration?
- what happens after 1 hr?
- active management of the third stage of labour?
- avg 10 mins, can be 3+
- remove under GA
- oxytocic drugs + controlled cord traction reduces risk of post partum haemorrhage
-prophylactic syntometrine 1ml OR Oxytocin 10 units
Cord clamping and cutting
Controlled cord traction
Bladder emptying
describe the cervical changes that occur during labour?
- softening (2)
- ripening (4)
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
What are Braxton Hicks contractions?
- regularity?
- resolve with what?
- pain?
- when do they occur?
-false labour
give a false sensation she is having real contractions
can thin thin the cervix but don’t lead to delivery
- irregular, do not increase in frequency or intensity
- ambulation or change in activity
- relatively painless
-can start 6 weeks in
not normally felt till second or third trimester
True labour contractions
- what are they?
- regularity?
- function?
- accompanying cervical changes?
- do they resolve?
-due to oxytocin stimulating the uterus to contract
-contractions evenly spaced and the time between gets shorter and shorter
get more intense and painful over time
-tighten the top part of the uterus and push bay downward into the birth canal
also promotes thinning of the cervix
- softenig, effacement, dilatation
- nope, painful!
Characteristics of uterine contraction
- where is the pacemaker located?
- the poles of the uterus do what?
- where are they most intense and what are the grades?
- normal frequency & duration?
-region of the tubal ostia, wave spreads in downward direction
waves from both ostia mean the contractions are synchronised
-upper segment contracts and relaxes, lower segment and cervix stretch, dilate and relax
fundal dominance
-second stage,
Mild, moderate and strong
-3-4 in 10 mins and initially last 10-15s with a max of 45s
