Lecture 14: Parturition - Preterm birth Flashcards
What is ‘pre-term labour’
Preterm: Labour before 37 weeks gestation (9%)
Very Preterm: Very preterm (~2%)
More then just dates, preterm is an abnormality: a failure of the uterine quiscence (a failure of the uterus to keep the baby in until the right time)
Which factors determine survival for a preterm baby?
Gestation and birth weight
Outcomes are good for a preterm baby at ___ weeks and ___g
28-29 weeks 1250 g
What are four factors that might cause premature birth?
- Stress - Bleeding - Infection - XS stretch
The earlier the labour occurs the more likely it is to have an ____ aetiology
Infectious/inflammatory
Why might cervical damage lead to preterm labour?
Weakens the bacteriostatic barrier (operculum)
Health problems of preterm birth?
- Immature fetus so often unwell
- Malpresentation: breech (butt 1st)
- Maternal co-morbidities
- complicated caesarean sections
- Risk of recurrence
- Poor health outcomes
Lung development determines _________
Limit of viability, determined by the fetal organ of gas exchange, the placenta.
If the type II cells in our lungs can’t effectively produce surfactant, which coats alveoli and reduces surface tension, and babies would require huge amount of energy to overcome this and expand lungs
What are the two main causes of iatrogenic preterm birth?
- Maternal disease (preeclampsia) - Foetal health (IUGR)
What is eclampsia?
A grand-mal convulsion due to endovascular inflammation
What is the highest risk factor for PTB?
Previous PTB
What are non-modifiable risk factors for PTB?
- Maternal age - Obstetric history - SES - Race
What are modifiable risk factors for PTB?
- Smoking - Need for cervical surgery - Reproductive technologies - No prenatal care
What other markers have been suggested for PTB risk screening?
- Serum biomarkers - Cervicovaginal fluids - Cervical length - Uterine activity
Foetal fibronectin is a biologial glue that sits between the ___ and ___
Decidua and chorion
After __ weeks pregnancy there is not supposed to be any fibronectin in the vagina
20
After __ weeks pregnancy there is not supposed to be any fibronectin in the vagina
20
Foetal fibronectin is a biologial glue that sits between the ___ and ___
Decidua and chorion
What other markers have been suggested for PTB risk screening?
- Serum biomarkers - Cervicovaginal fluids - Cervical length - Uterine activity
What are modifiable risk factors for PTB?
- Smoking - Need for cervical surgery - Reproductive technologies - No prenatal care
What are non-modifiable risk factors for PTB?
- Maternal age - Obstetric history - SES - Race
What is the highest risk factor for PTB?
Previous PTB
What is eclampsia?
A grand-mal convulsion due to endovascular inflammation
What are the two main causes of iatrogenic preterm birth?
- Maternal disease (preeclampsia) - Foetal health (IUGR)
How do we measure Fetal fibronectin in threatened PTL
- If positive: 30% deliver in 7-10 days
- Negative: 99.5% don’t deliver in 7-10days (what you want)
Used to decide who to transfer and who to treat with steroids
Checks if decidual lining is intact!
Intervention to suppress PTL: Tocolysis
Drugs: various modes of action, but the main ones are
- Ca2+ channel blockers** (Nifedipine)
- Oxytocin receptor blocker (atosiban $$$)
Used to be B2 agonist salbutammol, PG antagonists
Which antenatal corticosteroid is used to prevent respiratory distress syndrome?
Betamethasone
Which drug is administered to premature babies for neuroprotection?
MgSO4
MgSO4 is administered in babies under __ weeks ~ ___h before birth
30 weeks 6h before birth
When is progesterone gel most effective in suppressing labour?
- Cx length 10-20mm - 19-23 wks - Singletons - Prior STB
What are two effective interventions to prevent PTB in women with a short cervix?
Progesterone and cervical cerclage
Which antenatal corticosteroid is used to prevent respiratory distress syndrome?
Betamethasone
Which drug is administered to premature babies for neuroprotection?
MgSO4
MgSO4 is administered in babies under __ weeks ~ ___h before birth
30 weeks 6h before birth
When is progesterone gel most effective in suppressing labour?
- Cx length 10-20mm - 19-23 wks - Singletons - Prior STB
What are two effective interventions to prevent PTB in women with a short cervix?
Progesterone and cervical cerclage
