Labour and Monitoring Flashcards
wht are the contractions called than occur towards the end of pregnancy, but are not labour
Braxton Hicks conctractions
how are braxton hicks contractions differentiated from labour
they are irregular, do not increase in frequency/intensity and are usually painless
there will be no cervical changes
when are BH contactsions usually seen
they can start as early as 6 weeks but are usually seen in the 3rd triemster
outline the positive feedback mechanism of cervical stretch
cervical stretch from the foetus head causes oxtyocin release, which stimulates PG etc
as the baby is pushed further down, this mechanism is activated more and more
what is the most suitable femal epelvic shape for birth
gynaecoid
which type of pelvis is seen in tall ppl
android
which type of pelvis is assoicated with labour problems and why
anthropoid, the AP diameter>transverse. this means that the head is often high at term and labour can be difficult to start
what is the latent part of the 1st stage of labour
the cervix dilating from a closed os to 4cm dilatation
what is the active part of the 1st stage of labour
4-10cm dilatation (full)
what should the rate of dilatation of teh active part of the 1st stage be
no slower than 0.5cm/hr in PG and 1cm/hr in MG
how is progress in the 1st stage of labour monitored
uterine contractions and dilatation of the cervix
what is the 2nd stage of labour
from complete dilatation of the cervix to the passage of the baby through the birth canal
what is the max time NICE say it should take for the baby to be delivered after onset of 2nd stage of labour
4 hours
what are real labour contractions like
regular, increase in strenght, frequency and duration
fundal dominance, adequate resting tone
how long do normal contractions usualyl last and how frequent
3-5 in 10 mins, duration of 10 sec building up to 45 sec
what are the 7 cardinal movements of labour
engagement
descent
flexion
internal rotation
extension
external rotation
expulsion
when is the head considered engaged
when 3/5 of the head has entered the pelvis (2/5 still felt abdominally) - the widest diameter of the head has entered
how is descenet of the foetal head measured
in stations - the bottom of the baby’s head in relation to ischial spines
why does the baby do flexion
to ensure that the occipital part of the foetal skull enters the birth canal first as this is the smallest dm of foetal head - minimises moulding
what is another word for external rotation
restitution - return of teh foetal head to the correct anatomical position
which shoulder is delivered first
anterior
then posterior
how do you manage the 3rd stage
can manage it expectantly or actively
what does expectant 3rd stage involve
no drugs etc, delivery of placenta by maternal effort
what does active 3rd srage involve
the use of IM oxytocic drugs and controlled cord traction
how would you deliver the oxytocin for active management of 3rd stage
IM
is active or expectant management of 3rd stage preferred
no consensus - active reduces risk of PPH
how do you know if the placenta has separated from mum
uterus will contract, harden and rise
the umbilical cord will lengthen permanently
blood
what are the 2 different ways in which the placenta can separate
- matthew duncan - from edges first, middle last
schultz- from the middle first
can TENS be used for analgesia during birth? and what is it
yes, electrical stimulus is applied to the skin over the back where the pain is through electrodes
what is Entonox
a half and half mix of O2 and NO (laughing gas)
why is Entonox good to use
it has no effect on the baby
what stronger pankiller can be used as analgesia during labour
diamorphine (heroin!) - less commonly used
how is diamorphine adminstered
deep IM injection, with an anti emetic eg prochloperazine or cyclizine
what are the risks of using diamorphine, and what steps are taken to avoid these
- respiratory depression in baby - dont use wtihin 2-3 hours of delivery
- mother: resp depression, constipation, headache, euphoria, nausea, vomiting, itch, confusion etc etc
what can be adminstered to counteact the effects of diamorphine
naloxone - opioid antagonist
how does resp depression from diamorphine manifest in the baby
bradycardia and decreased variability on CTG
pain sensation - how is pain from the top of teh pelvic organs (ones that touch the peritoneum) transmitted
the visceral afferents run alongside synmpathetic fibres and enter the spinal cord between levels T11 and L2
how is pain from the inferior aspects of the pelvic organs, that is not in contact with the peritoneum, transmitted
the visceral afferents run back with parasympathetic fibres and enter the spinal cord between S2 and S4
what structure marks the boundary between the pelvis and perineum
levator ani (pelvic floor)
how does pain transmission differ between teh pelvis and perineum
above the levator ani, the pain fibres run back with the parasympathetic fibres (S2-4)
below, the pain is sensed by the pudendal nerve, which runs back and enters the spinal cord between S2 and 4. this would be felt as localised pain in the perineum
where is a spinal anaesthetic injected into
subarachnoid space L3/4
where is teh epidural injected into
epidural space, at L3/4 region
what is found in the epidural space
loose fat, tissue and veins
epidural adverse effects - low bood pressure
how does this happen
it blocks the sympathetic system so causes vasodilatation - sudden and profound hypotension
epidural adverse effects - hypotension
what precautions are taken
a cannula is inserted into the arm incase IV fluids are needed quickly and BP is monitored
epidural adverse effects - hypotension
what effect would this have on baby
reduced perfusion could cause foetal hypoxia
epidural adverse effects - bladder problems
person cant feel bladder so often goes into urinary retention - insert a catheter
epidural adverse effects - what is often felt in the legs
heavy/weak legs are common
numbness and tingling
epidural adverse effects - headache
if the injection goes too deep and makes a hole into the subarachnoid space there can be CSF leakage. if too much CSF is lost there will be a severe headache that can last a few days unti CSF replenishes
the headache is worsen when standing up and relieved by lying down (gravity)
epidural adverse effects - total spinal syndrome
if the anaesthesia is accidentally injected into the spinal cord –> unconsciousness and general anaesthesia
the mother will need to be intubated ventilated and receive CV support
what negative effect can an epidural have on labour
as the mother cant feel when it is time to push the 2nd stage may be prolonged
she may need help from doctors and midwives
give an example of a local anaesthetic used in spinal anaesthesia
bupivacaine
when is spinal anaesthesia generally used
in C section or assisted vaginal delivery
why are you less likely to use spinal anaesthesia in normal labour
it blocks the feeling of uterine contractions so the mum finds it arder to push
it also can wear off before labour is complete, whereas an epidural you can leave in and give top ups
when would a pudendal nerve block be used
localised effect on perineum
used for episiotomy, forceps or perineal stitching post delivery
why are NSAIDs not used as anaesthesia for labour
they inhibit COX which would produce PG - these are needed to soften the cervix and cause uterine contractions
also cause premature close of patent ductus arteriosus and oligohydramnios
what effect do opioids have on baby abd breastfeeding
poor suckling in baby
delayed onset of breastfeeding
when should mum first be able to feel foetal movements
around 20o weeks
how should foetal movements change over the course of labour
intensity (strength) should increase till about 24 weeks, then plateau, then may decrease close to labour as baby doesnt have much space
frequency should stay teh same throughout
what should mum do if foetal movements decrease in frequency
see a healthare provider to asses baby further - could be first sign of foetal compromise
when is CTG used to assess FHR
Intermittent auscultation with Pinard or handheld Doppler for low risk pregnancies, CTG monitoring for high risk.
normal baseline heart rate
110-150
how does foetal hypoxia change baseline rate
initally tachycardia, and then bradycardia?
how many contractions is normal in 10 mins
3-5
what may >5 contractions in 10 mins indicate
hyperstimulation of the uterus
what is variability
the variation of the foetal heart rate between beats, seen as deviations in the baseline rate
what is normal variability
5-25
what could cause a reduction in variability
baby sleeping, hypoxia, tachycarida, drugs, prematurity etc
what are accelerations
a transient increase in the baseline foetal heart rate by >15bpm for >15 seconds
what does teh presence of accelerations indicate
need to be there for an antenatal CTG to be normal
dont need to be there in labour
what are decelerations
- Transient decrease in baseline foetal heart rate > 15bpm for >15 seconds
what do early decelerations look like on CTG
the peak and trough will match
what do early decelerations indicate
these are a normal finding, associated with foetal head compression during labour
what are typical variable decelerations like
they have shouldering, last <60 sec
what are typical variable decelerations a sign of
normal physiological response to transient acute hypoxia from cord compression during a contraction reflecting a well oxygenated foetus
what are atypical variabel decelerations like
W shaped (biphasic), no shoulders, last >60 seconds, baseline rate doesnt return to normal after
what do late decelerations look like on CTG
the trough of each deceleration is after the peak of each contraction
what do late decelerations mean
they are a worrying sign - may indicate foetal hypoxia and acidosis
how is the overall assessment of the CTG classified
reassuring, non-reassuring (1/4 abnormal feature) and abnormal (≥2)
management of a non-reassuring CTG
- Maternal position – lying supine causes aortocaval compression by gravid uterus, reducing maternal cardiac output
- Dehydration
- Low blood pressure
- Hyperstimulation – if contraction frequency >5 and oxytocin being infused, stop/reduce it. If this doesn’t help or oxytocin is not being given – give tocolytic to relax uterus e.g. terbutaline (beta 2 agonist)
- Infection
- Rapid progress – sudden head decent
how is hyperstimulation managed
- if on oxytocin stop it
- if this doesnt work/not on –> tocolytic eg erbutaline
management of abnormal CTG
same as non reassuring
if the cervix is fully dilated and the foetus is easily deliverable perform an instrumental delivery
scalp stimulation - describe this
FBS
contraindications to FBS
- Maternal infection
- Bleeding disorders
- Breech position
- Prematurity (<34 weeks)
management of sustained foetal bradycardia >3 mins
emergency- obstetric review now
- Abdominal and vaginal exam to assess for cause
- Change maternal position
- Rapid IV fluid for acute hypotension
- If heart rate doesn’t recover à deliver now
