PRETERM LABOUR Flashcards
What is the definition of preterm labour?
Labour occurring after 24 weeks and before 37 weeks of pregnancy.
Up to what point of gestation should attempts be made to stop a premature labour and why should these attempts be made?
Up to 34+0 weeks
Need to delay long enough to administer corticosteroids to the mother, which will boost fetal lung surfactant production and therefore reduce neonatal respiratory distress.
What corticosteroids can be given to mothers in cases of premature labour to increase fetal surfactant production?
Betamethasone or dexamethasone.
Two IM injections given 12-24 hours apart
What is the mortality rate of preterm babies?
42 in 1000 livebirths
What is the incidence of preterm labour in England and Wales?
7.6% but this figure is increasing
What are the risk factors for premature labour?
Previous preterm labour Smoking Low SEC BMI below below 19 Lack of social support Afro-Caribbean ethnicity Extremes of reproductive age (less than 20 or more than 35) Domestic violence Bacterial vaginosis Chronic medical conditions
What are the main causes of preterm delivery?
Infection eg chorioamnionitis, maternal pyelonephritis
Uteroplacental ischaemia eg abruption
Uterine overdistension eg polyhydramnios, multiple pregnancy
Cervical incompetence
Fetal abnormality
Iatrogenic - because of threat to mother or babies life eg pre-eclampsia
What are the main pathogens implicated in preterm labour?
Sexually transmitted: Chlamydia, Trichomonas, Syphilis, Gonorrhea
Enteric organisms: E. coli, Strep fecalis
Bacterial vaginosis: Gardnerella, Mycoplasma and anaerobes
Group B streptococcus (would be very heavy growth)
What do we call palpable uterine contractions where the cervix remains closed?
Threatened preterm labour
What would you examine in a pregnant women who presents with symptoms consistent with preterm labour?
Abdominal tenderness Uterine tenderness Uterine tone Uterine contractions Fetal lie, presentation and engagement
What investigations should you do in a pregnant women who appears to be having preterm labour? Why?
Ultrasound - to check abnormal lie and presentation
Sonicaid - if 25+6 weeks of gestation or less to check fetal heart beat
Cardiotocograph - if 27 weeks of gestation or more to check fetal heart
Kit to check for presence of fetal fibronectin - the absence of this would indicate that delivery is less likely which may assist management decisions with regard to tocolysis
Urinalysis - check for UTI infection
What is the 11 point management checklist (including investigations) for a patient who presents with threatened preterm labour?
- Assess for signs of precipitant - sepsis, polyhydramnios, abruption, pre-eclampsia
- Take bloods and do urinalysis
- Determine frequency and regularity of contractions
- Perform sterile speculum to examine cervix (open or closed). Take high vaginal and endocervical swabs.
- Start fetal heart monitoring
- Ascertain fetal presentation (breech or cephalic) with ultrasound
- Give corticosteroids
- Give Abx if ruptured membrane or sepsis
- Consider tocolysis
- Contact paediatricians
- Discuss mode of delivery.
What does tocolysis mean?
The administration of drugs to reduce uterine activity
What are the factors that determine whether tocolysis is necessary in a women is is going into preterm labour?
Cervical dilatation
The need to administer steroids and allow time for them to be effective
Need for in utero transfer (breech)
What are the different drugs that can be used as tocolytics, drugs that try and stop contractions in women who have gone into preterm labour? For each class give an example that is used.
Oxytocin receptor antagonists - atosiban
Calcium channel blockers - nifedipine (not licenced in the UK)
Beta agonists - salbutamol, ritodrine, terbutaline (IV)
NSAIDs (prostaglandin inhibitors) - indomethacin
Nitric oxide donors - GTN (transdermal patch)
What are the potential side effects of oxytocin receptor antagonists, used as tocolytics?
8% of women experience headaches
What are the potential side effects of calcium channel blockers such as nifedipine when used as tocolytics?
Headache
Flushing
Tremor
What are the potential side effects of beta agonists such as salbutamol when used as tocolytics?
Side effects are very common (80% of women):
Tachycardia (both mother and fetus) Headache Tremor Hyperglycaemia Hypokalaemia Pulmonary oedema MI
What are the potential side effects of NSAIDs such as indomethacin when used as tocolytics?
Mother:
Heartburn
Nausea
Fetus:
Premature closure of ductus arteriosus
Reduced renal function causing oligohydramnios
What are the contraindications for the use of tocolytics?
Maternal illness that would be helped by delivery (eg pre-eclampsia)
Evidence of fetal distress
Chorioamnionitis - intra-amniotic infection
Significant vaginal bleeding, particularly if abruption is suspected
Already ruptured membranes
Should all women who go into preterm labour be given antibiotics?
Those women whose membrane has ruptured before term should have prophylactic erythromycin.
If membrane is intact, the mother should be screened for infection with vaginal and cervical swabs and blood cultures if pyrexial) and only given antibiotics if there are signs of infection.
What is cervical incompetence or insufficiency and why is it an issue in pregnancy?
This is when the cervix starts to shorten and open too early during a pregnancy. It can causing either a late miscarriage or preterm birth by allowing the membrane to prolapse and then rupture.
How can we treat cervical incompetence or insufficiency?
Cervical cerclage can be performed. This is the insertion of a suture into the cervix to reduce the prolapsed membrane.
How should preterm babies be delivered?
There is no evidence to suggest that caesarian section is any safer than vaginal birth in preterm babies.
What does PPROM stand for with regard to obstetrics?
Preterm prelabour rupture of membranes
What is the principal issue with preterm prelabour rupture of the membrane?
Sepsis of both the mother and the fetus.
How do you manage a patient with preterm prelabour rupture of the membrane?
Check fetal lie and presentation - risk of cord prolapse
Digital examination should not be done - unless there are obvious signs of labour - due to risk of infection introduction
Check for symptoms of clinical chorioamnionitis (fever, rigors, green or brown or foul smelling vaginal loss, tender uterus on palpation)
CTG
Blood tests
Administration of prophylactic erythromycin / treat sepsis
Administration of corticosteroids to improve fetal lung maturity
How long after preterm prelabour rupture of membrane will a women normally go into labour?
Within 72 hours
If a women whose membrane ruptures preterm and prelabour does not go into labour within 72 hours at what point is the target delivery date?
34+0 weeks
Either by induced labour or caesarian section.
What tocolytics are used in women with PPROM?
None. They are never used.
What antibiotics should be avoid in someone with PPROM due to their association with necrotising enterocolitis in the infant?
Co-amoxiclav
