9.2 Premature Labour Flashcards
What is SROM?
Spontaneous rupture of membranes (amniotic sac ruptures, releasing amniotic fluid)
What is PROM?
Prelabour rupture of membranes (before onset of labour)
or
Prolonged rupture of membranes (rupture more than 18hrs before delivery)
What is P-PROM?
Preterm prelabour rupture of membranes (ruptured before labour and before 37 weeks, ie prem)
At what gestation is a baby premature?
Before 37 weeks
At what gestation is a baby viable?
viable at 23 weeks (10% chance; no resus if not showing signs of life)
higher survival at 24 weeks (full resus)
What are the WHO classifications on prematurity?
under 28 weeks; extreme prem
28-32; very prem
32-37; moderate to late prem
What prophylaxis options do you have to prevent preterm labour?
Vaginal progesterone
Cervical cerclage
How does progesterone prophylactically prevent preterm labour?
Decreases activity of the myometrium and prevents cervix remodelling in preparation for labour.
Who is offered prophylactic progesterone for preterm labour?
Between 16 and 24 weeks for women with a cervical length less than 25mm on vaginal US
How does cervical cerclage prophylactically prevent preterm labour?
Puts a stitch into cervix to add support and keep it closed (under spinal or GA)
(removed once woman goes into labour)
Who is offered prophylactic cervical cerclage for preterm labour?
Between 16 and 24 weeks for women with a cervical length less than 25mm on vaginal US
and had
a previous premature birth or cervical trauma (colposcopy or cone biopsy)
What is a rescue cervical cerclage?
offered between 16 and 27+6 weeks when there is cevical dilatation without rupture of membranes (aims to prevent progression)
What tests could be done to confirm PPROM?
- insulin-like growth factor-binding protein-1 (IGFBP-1) is in amniotic fluid and can be tested for in vaginal fluid if there is doubt about ROM
- placental alpha-microglobin-1 (PAMG-1) is alternative to IGFBP-1
How do you manage PPROM?
- prophylactic Abx erythromycin 250mg 10days
- induction of labour is offered from 34 weeks… or 37 weeks now
What is preterm labour with intact membranes?
regular painful contractions and cervical dilatation before 37 weeks and without ROM
How do you diagnose preterm labour with intact membranes when less than 30 weeks gestation?
Diagnosis on clinical assessment alone
- speculum for dilatation
(regular painful contractions and cervical dilatation before 37 weeks and without ROM)
How do you diagnose preterm labour with intact membranes when more than 30 weeks gestation?
Transvaginal ultrasound to assess cervical length:
>15mm mean preterm labour unlikely;
<15mm offer management for preterm labour.
(regular painful contractions and cervical dilatation before 37 weeks and without ROM)
In preterm labour with intact membranes greater than 30 weeks you need transvaginal ultrasound to diagnose - what if you can’t get US / what is the alternative?
Fetal fibronectin greater than 50 ng/ml
this is the “glue” between the chorion and the uterus
5 options for improving outcomes in preterm labour?
- tocolysis with nifedipine (CCB suppresses labour)
- corticosteroids (before 35 weeks reduce ARDs, NEC, ICH)
- magnesium sulphate IV (before 34 week to protect baby’s brain)
- delayed cord clamping or cord milking
- fetal monitoring (CTG or intermittent auscultation)
What is tocolysis?
stopping uterine contractions
Name two drugs for tocolysis?
1st line; nifedipine (CCB)
2nd line; atosiban (oxytocin receptor antagonist) when nifedipine contraindicated
At what gestation can tocolysis be used?
between 24 and 33+6 weeks
How long does tocolysis work for and what is the extra time used for?
short-term measure eg extra 48 hrs
- further fetal development
- administer steroids
- transfer to specialist unit (eg with NICU)
At what gestation can you give corticosteroids?
between 24 and <35 weeks (34+6)
What is an example regimen of maternal corticosteroids?
two doses of IM betamethasone, 24 hrs apart
reduce ARDs
What medication can protect the fetal brain?
IV magnesium sulphate
reduces risk and severity of cerebral palsy
At what timing can IV magnesium sulphate be given?
within 24 hrs of
preterm delivery less than 34 weeks
How is IV magnesium sulphate administered?
bolus and then infusion for up to 24 hrs or until birth
What is the risk of IV magnesium sulphate?
Magnesium toxicity in mum
- monitor four hourly
What is monitored 4 hourly when on IV magnesium sulphate?
Signs of toxicity:
- reduced resp rate
- reduced BP
- absent reflexes (patella)
