Labour - Special Circumstances Flashcards
What is successfulness of induction depend on?
State of ‘favourability’ of the cervix
often scored out of 10 as the ‘Bishop’s score’ - the lower the score the more unfavourable the cervix
Five things are assessed and given a score based on different criteria (minimum score is 0 and maximum is 13):
Fetal station (scored 0 – 3) Cervical position (scored 0 – 2) Cervical dilatation (scored 0 – 3) Cervical effacement (scored 0 – 3) Cervical consistency (scored 0 – 2)
A score of 8 or more predicts a successful induction of labour. A score below this suggests cervical ripening may be required to prepare the cervix.
What are the components of the bishop’s score?
Cervical ‘consistency’
Degree of effacement or early dilation
How low the head is in the pelvis (station)
Cervical position (anterior or posterior)
What are the methods of induction?
Membrane sweep involves inserting a finger into the cervix to stimulate the cervix and begin the process of labour - done over 40
Vaginal prostaglandin E2 (dinoprostone) involves inserting a gel, tablet (Prostin) or pessary (Propess) into the vagina. This stimulates the cervix and uterus to cause the onset of labour.
Cervical ripening balloon (CRB) This is used as an alternative where vaginal prostaglandins are not preferred, usually in women with a previous caesarean section, where vaginal prostaglandins have failed or multiparous women (para ≥ 3).
Artificial rupture of membranes with an oxytocin infusion can also be used to induce labour, although this would only be used where there are reasons not to use vaginal prostaglandins. It can be used to progress the induction of labour after vaginal prostaglandins have been used.
How does cervical sweeping work?
Passing a finger through the cervix and stripping between the membranes and the lower segment of the uterus - at 40 weeks, this reduces the chance of induction and postdates pregnancy, but can be uncomfortable
How does induction with prostaglandins work?
gel/slow-release preparation is inserted into the posterior vaginal fornix.
best method for nulliparous women and in multiparous women.
Starts labour OR ripeness of the cervix is improved to allow amniotomy
How does ARM / oxytocin work?
Forewaters are ruptured with an amnihook
oxytocin induction is then started within 2 hours if labour has not ensued. oxytocin is often used alone if spontaneous rupture of membranes have already occurred, although PGs are effective
What are the indications for induction of labour?
Foetal indications - high risk situations: prolonged pregnancy suspected IUGR or compromise Antepartum haemorrhage Poor obstetric history prelabour term rupture of membranes
Materno-foetal indications - pre-eclampsia and maternal disease (e.g. diabetes)
Maternal indications - social reasons and in utero death
routine indications - studies show lowest perinatal and infant mortality rate is achieved by delivery at 38 weeks
What are the absolute contraindications of induction?
Acute foetal compromise - abnormal CTG
Abnormal lie
Placenta praevia
Pelvic obstruction
> 1 C-section
What are the relative contraindications of induction?
> 1 C section and prematurity
What are the complications of induction?
Foetus - increased risk due to indications and drugs (CTG indicated)
Induction increases time spent in early labour - woman should be warned of this
labour may start to fail or be slow due to inefficient uterine activity - or overactivity of the uterus can occur. hyper stimulation causes foetal distress and even uterine rupture
Complications - PPH, intrapartum/postpartum infection, prematurity, instrumental delivery or C-section
What are the contraindications of VBAC (vaginal birth after caesarean)?
all absolute indications for C-section
Vertical uterine scar
Previous uterine rupture
Multiple previous C-sections
What % of women will deliver vaginally and by C-section if VBAC is attempted?
72-75% women will deliver vaginally
The others will require an emergency C-seciton in labour
What are the factors associated with increased success of VBAC?
spontaneous labour
Interpregnancy interval <2 years
Low age and BMI
Caucasian race
Previous vaginal delivery
Previous elective C-section or due to foetal distress (not dystocia)
In what % of VBACs does uterine rupture occur in?
1 in 200
What is the risk of foetal mortality with VBAC?
same risk as found in 1st labour
Why is delivery in hospital and with CTG monitoring advised?
Scar rupture
induction usually avoided as it is associated with a higher risk of rupture
augmentation also increases the risk of scar rupture
What does scar rupture usually present with?
Foetal distress Scar pain Cessation of contractions Vaginal bleeding Maternal collapse
In what % of women does prelabour term rupture of the membrane occur in?
10% women after 37 weeks
60% will start labour pithing 24 hours
How does PROM present?
gush of clear fluid, which is followed by uncontrollable intermittent trickle
often confused with urinary incontinence
Point of care tests (actim PROM) may help where the diagnosis is not clear
Few only have hind water rupture - liquor leaks, but membranes remain intact in front of the foetal head
What are the risks of PROm?
Cord prolapse - rare and usually a complication of transverse lie or breech presentation
Neonatal infection - small but definite risk - increased by vaginal examination, presence of GBSand increased duration of rupture. Therefore, sterile speculum but don’t do VE
What needs checking in PROM?
Lie and presentation - vaginal examination is usually avoided, but may be performed in a sterile manner if there is risk of cord prolapse - foetal auscultation or CTG are performed
What are the management options of PROM?
admission
regular observations to ensure chorioamnionitis is not developing
oral erythromycin should be given for 10 days
antenatal corticosteroids
delivery should be considered at 34 weeks of gestation - there is a trade-off between increased risk of maternal chorioamnionitis with a decreased risk of respiratory distress syndrome as the pregnancy progresses
