Unit 7; Labour Flashcards
What are the different trimesters of pregnancy?
First trimester is from week 1 to the end of week 12
Second trimester is from week 13 to the end of week 26
Third trimester is from week 27 to the end of pregnancy
What are the key third trimester antenatal checks?
Three key tests: blood pressure, urine and uterus size using tape measure
28 weeks - 3 kt and first anti-D rhesus treatment if needed
34 weeks - birth plan, discuss pain relief, second anti-D treatment if needed
36 weeks - external cephalic rotation if needed, info on caring for a newborn, post natal care for mother and screening of baby, 3kt
41 weeks - 3kt, may be offered a membrane sweep and discuss induction of labour
What are the additional third trimester checks for first time mothers?
Three key test of blood pressure, urine analysis and uterus size using a tape measure
31 weeks : 3kt
40 weeks: 3kt
When is labour normally induced and what are the reasons for this?
Labour is normally induced between 40 and 42 weeks
Past 40 weeks, efficient of placenta decreases and may start to seperate from endometrium, increased risk of still birth, larger baby
Premature labout may be induced in the case of pre-eclampsia, foetal distress, restircted foetal growth or baby is too large for a vaginal delivery.
How does a membrane sweep induce a labour?
Seperates the amniotic sac from the cervix
Triggers the release of prostaglandins, triggering contractions and soften and stretch cervical collagen.
Can not be done is the baby is not cephalic, in a low-lying placenta or if increased risk of bleeding.
How does an amniotomy induce labour?
Puncture small holes in the amniotic sac, slow loss of amniotic fluid, pressure from this can cause the foetal head to engage and triggers cervical dilation and effacement.
Done using a speculum and a needle
Negatives: reduces boyancy for the foetus, risk of umbilical prolapse or uterine infections
How does oxytocin induce labour?
Given IV
Reduces levels of estrogen and progesterone by negative feedback.
Bind to receptors causing stronger and more frequent contractions.
Negative: can increase speed of labour increasing risk of perineal tear, uterine rupture and may decrease blood flow to the foetus
What are the stages of labour for the foetus?
Engagement - widest diamter of the foetus has passed into the widest diamater of the maternal pelvis (often in an occipiputtransverse position)
Descent - foetus moves down the maternal pelvis due to contractions, maternal effort and pressure from amniotic fluid
Flexion - foetal head comes into contact with pelvic floow muscles, flexes neck, reduces the diameter of the presenting part
Internal rotation -shape of pelvic floor muscles causes the foetus to rotate into an occipioanterior position,
Crowning - at 10cm dialted, foetal head no longer receeds between contractions
Extension - head begins to be deliver neck extends to stretch perineum
head delivery
External rotation and restitution - to realign with the shoulder in occiput transverse
Shoulder delivery
What are the key hormonal changes during labour?
Progesterone decreases - removes inhibitory effect on smooth muscle contraction
Oxytocin increases - stimulates contractions, creates mothering response
Prolactin - prepares to breastfeed, produce colostrum
What is the role of stress hormones during pregnancy?
Cortisol and adrenaline can inhibit the affect of oxytocin as compete for the same receptors, this can inhibit contractions and prolong labour
However, stress hormones do peak towards the ends of labour, this provides the energy for the maternal effort to aid delivery.
What are the different types of pain relief available during labour?
Epidural
Entonox (gas and air)
Pethidine
TENs
Water birth
How are water births thought to reduce pain in labour?
Decreased stress hormones
Increased endoprhins
Allows more flexibility to change positions to relive pressure
However can prolong labour
Heat detection role in the pain gate theory
How does entonox reduce pain in labour?
High low oxygen and high flow nitrous oxide
Nitrous oxide - mild agonist of opioid receptors
Oxygen - encourage endorphin release
Negatives: mild pain only, can cause hallucinations and nausea.
How does pethidine reduce pain?
Is an intramuscular opiod given in the thights or gluteal region
At the presynpatic neurone - inhibits Ca2= influx
At the post synpatic membrane - increase K+ efflux
Receptors are GPCRs
Decreases the probability of an action potential occuring
INhibits GABA and noradrenaline release
Works within 20 minutes affects last for 2 hours.
How do epidurals reduce pain?
Local anaesthetic
Blocks nerve endings
Blocks voltage gated Na+ ion channels
Typically given between T10 and L1
Must be given by an anaesthetic, can prolong labour, loose bladder control, risk of nerve damage
How is a newborns health assessed using an APGAR score?
Activity - muscle tone, passive movement, able to flex, stuck flexed, active
Pulse - indicates HR
Grimace - response to stimuli, sound, light, touch, reflexes
Appearance - facial abnormalities, cleft lip, blueness
Respiration - strong cry,
Each section is scored out of three, three being the healthiest, can indicate is emergency care is needed
