abnormal labour Flashcards
induction of labour - incidence
~1/5 pregnancies
can be before or after due date
need fetal monitoring (higher risk)
need for cervical ripening - prostaglandins, balloon
what is induction
an attempt is made to instigate labour artificially using medications and/or devices to ripen cervix
followed usually by artificial rupture of membranes (amniotomy)
what is Bishop’s score
used to clinically assess the cervix
higher score = more progressive change there is in the cervix
indicates that induction is likely to be successful
components of Bishop’s score
process of induction of labour
amniotomy once cervix has dilated and effaced
once amniotomy performed, IV oxytocin used to achieve adequate contractions (unless contractions spontaneously start) - aim for 4-5 contractions in 10 mins
what Bishop score is considered favourable for amniotomy
7
what is an amniotomy
artificial rupture of the fetal membranes
usually using sharp device e.g. amnihook
indications for induction
diabetes
post dates - term + 7days
maternal need for planning of delivery e.g. on treatment for DVT
fetal reasons - growth concerns, oligohydramnios
social/maternal request
intrapartum complications - powers, passages, passenger
what may inadequate progress in labour be due to?
powers - inadequate uterine activity
passages - cephalopelvic disproportion (CPD), other reasons for obstruction e.g. fibroid
passenger - malposition, malpresentation
fetal distress
evaluating progress in labour
combination of abdo and vaginal examiantions to determine - cervical effacement, cervical dilatation, descent of the fetal head through the maternal pelvis
what define suboptimal progress in the active first stage of labour
cervical dilatation:
<0.5cm per hour for primagravid women
<1cm per hour for parous women
inadequate uterine activity
inadequate contractions = fetal head will not descend and exert force on cervix = cervix will not dilate
how can contractions be increased
what is important to exclude
synthetic IV oxytocin to the mother
increases strength and duration of contractions
exlude an obstructed labour in these circumstances, stimulation could result in ruptured uterus
what is cephalopelvic disproportion
genuine CPD is relatively rare
means that the fetal head is in the correct position for labour but too large to negotiate the maternal pelvis and be born
caput (swelling on the baby’s head) and moulding (fetal skull bones start to cross) develop
causes of obstruction in labour
CPD
placenta previa
fetal anomaly e.g. hydrocephaly
fibroids
malposition of the baby
much more common than malpresentation
occipitoanterior is ideal presentation for birth
fetal head is in a suboptimal position for labour and relative CPD occiprs - occipitoposterior and occipitotrasnverse
what is the ideal presentation for baby
longitudinal lie
vertex presentation
malpresentation of baby
breech presentation - can be born vaginally
trasnverse - need C section
how do we determine position of baby
vaginal examination feeling baby’s head (fontanelles)- posterior is triangle, anterior is diamond
fetal distress
why does it happen
fetuses are well equipped to deal with stress of labour but some fetuses will not be able to cope
important to avoid causing too many contractions (uterine hyper-stimulation) as this can result in fetal distress due to insufficient placental blood flow
main causes of fetal distress - hypoxia, infection
rare causes - cord prolapse, placental abruption, vasa praevia
many cases of suspected distress have no cause found
fetal monitoring - how is this done
intermittent ausculation of fetal heart
cardiotocography (CTG)
fetal blood sampling
fetal ECG
intermittent auscultation frequency increases during 2nd stage - every 5 mins
fetal blood sampling
speculum used to take fetal scalp blood sampling
used when abnormal CTG
what can we measure from fetal blood sampling
pH and base excess
lactic aid
pH gives a measure of likely hypoxaemia
mum has to be ~4cm dilated
can’t tell us about fetal bleeding or sepsis
