Week 10-14 Flashcards
Define: Pre-term birth
Labour that occurs after 20 weeks gestation and before 37 completed weeks gestation.
What is the incidence of pre-term birth in Australia
8.2% in Australia
In 2014 what was the % of pre-term births in NSW
7.7%
When are most pre-term infants born
32-36 weeks
What is the perinatal mortality rate for pre-term births
7.6 per 1000 births
How does infection relate to pre-term birth
Inflammatory cytokines or bacterial endotoxins can stimulate prostaglandin release directly or indirectly by stimulating the release of corticotrophin-releasing hormone (CRH)
What are the contributing risk factors for pre-term birth
- Past obstetric history: repeated pre-term birth, miscarriages or terminations
- Birth following ART and ovulation induction
- Birth among women >34 years
- Infection: bacterial vaginosis
- Demographic: social disadvantage
- Medical conditions: diabetes, high blood pressure
- Current pregnancy: placental abruption, pre-eclampsia
- Behavioural: stress, psychological issues
What are the known causes of pre-term birth
- Infection and inflammation
- Multiple pregnancy (40-65% twins end in preterm birth).
- Medically assisted conception e.g. fertility drugs, IVF/GIFT (20% risk of preterm birth).
- PROM (25-30%).
- Short pregnancy interval.
- Polyhydramnios.
- ‘Incompetent’ weak cervix (35%).
- Premature separation of placenta.
- Excessive use of alcohol, smoking and narcotics in pregnancy.
- A genetic basis of preterm birth.
- APH.
- 50% have no obvious cause.
Pre-term therapy
Explain: Tocolytic therapy
the attempt to stop or limit uterine contractions in preterm labour using drugs.
Explain: Tocolysis
Betamimetics: e.g. I.V salbutamol, terbutaline, ritodrine are βeta-adrenergic agonists and relax smooth muscle cells in the uterus.
- side effects: rapid pulse, chest pain, headaches.
- Contraindicated in:cardiac disease. May delay labour by 48 hours, can be used on hospital transfer.
Calcium channel blockers: e.g. oral nifedipine reduce muscle contraction by controlling the influx of calcium across the plasma membrane.
Explain: MgSO4
MgSO4 for neuroprotection of the preterm infant, to minimise the risk of cerebral palsy.
Indications:
Preterm fetus < 30 weeks gestation.
If preterm birth expected in <24 hours, treatment to commence as close as 4 hours before birth.
4g loading dose and titrated.
Used for singleton or twin pregnancies.
What are the contraindications to treatment of premature labour
Contraindications to stopping a labour:
- Mature fetus >34 weeks.
- Fetal death.
- Fetal anomaly incompatible with life.
- SGA/IUGR related to unfavourable intrauterine environment.
- Other fetal compromise/fetal distress on admission.
- Active haemorrhage.
- Intra-amniotic infection/chorioamnionitis.
Pre-term birth
What is the labour management for expectant delivery
(Tocolysis contra-indicated if cervix is dilated)
- Commence IMI steroids
- Have maternal and neonatal specialist’s notified and ready
- Conduct regular labour observations
- Monitor fetus
Pre-term birth
What is the delivery management for pre-term birth
Be prepared for:
- rapid 2nd stage
- possible fetal distress
- neonatal resuscitation equipment/ ready for TF to NICU
- Contemporaneous documentation
Pre-term birth
What is the subsequent midwifery care is a woman is admitted to the ward
- administer IV fluids, tocolytics, antibiotics and 2nd dose of steroids
- fetal welfare assessment
- discuss premature outcomes with parents
- maternal assessment (obs and abdominal palpations)
- r/v by specialist
What is the midwifery care on admission to the BU for delivery
- take patient history
- prepare room (rests equipment ready)
- request additional personnel
- CTG monitoring
- type of birth
Define: Premature rupture of membranes
Rupture of the amniotic sac prior to 37 weeks gestation
Premature rupture of membranes
What are the maternal and fetal effects of PROM
Maternal
- 50% deliver within 1 week
- maternal sepsis
Fetal
- prematurity
- fetal infection (chorioamnionitis)
- fetal compromise
- developmental abnormalities
- possible TOP
How is premature rupture of membranes diagnosed?
NO vaginal examination
- sterile speculum
- amnicator test
- observe for labour signs
What % of multiple pregnancies end in preterm delivery
15%
What is the most common pregnancy complication relating to twins
Polyhydraminos- causing premature labour and prematurity
Diagnosis of twins
How are twins diagnosed
Suspected
- IVF
- Severe hyperemesis
- increased pregnancy discomforts
- conditions (GDM, pre-eclampsia, LGA)
- polyhydraminos
Confirmation
- U/S examination
Multiple pregnancies
What are the complications
- anaemia
- placenta previa
- polyhydraminos and preterm labour
- malpresentations
- pre-eclampsia and GDM
- PPH
- Growth restriction and IUD
Define: PPH
Blood loss of 500ml or more during and after childbirth