Lecture 16: Preterm Labour Flashcards
What is preterm?
<37 weeks
VPTB <32 weeks
EPTB <28 weeks
What is spontaneous vs indicated preterm birth?
Indicated is dr initiated because of threat to either mum or babe.
Spontaneous prematurity is a pathology of uterine quiescence
What are the possible pathological processess of premature baby?
Endocrine - fetal/maternal stress
Inflammation / infection
Decidual haemorrhage
Uterine distension
Leads to abnormal stimulation and thus labour
What possibly triggers the cascade leading to stimulation and labour?
Infammation Mechanical Hormonal Fetal (genomic/HPA) melatonin and circadian rhythms
What causes pre-term activation of HPA, and what are two examples?
Increased fetal or maternal stress -> Prem. activation of fetal HPA
i. e Uteroplacental vascular insufficiency (FGR or PET) and thus spon. PTB
i. e Maternal major psychological stress can activate HPA axis
What sort of infections can cause PTB?
- Ascending infection into membranes i.e STI
Degrades barrier of cervix and infiltrates around membranes -> Inflammation (i.e because of phospholipase A2 or endotoxins) (this inflam interferes with normal pathway, enhancing the processes)
How does decidual heamorrhage (Pathology) come about?
Damaged decidual blood vessels -> Retroplacental hematoma
Thrombin activation as part of the normal coagulation cascade.
- > Directly increases myometrial contractions
- > upregulates MMPs -> pprom
- > Inhibits expression of progesterone receptors i.e activates as progesterone withdrawal.
What are some causes of distension and what physiological changes do they cause that possible lead to labour?
- Multiple pregnancy
- Polyhydramnios
- Enhanced stretching
- Increased CAP
- Increased connexin 43
What is cervical insufficiency?
- Dilation or effacement without contractions (i.e conditions for labour)
- Usually previable loss
- Clercage may be helpful
Is there strictly one pathophysiology?
No they all interrelate i.e slide 14
What are the short term costs of preterm?
Many different impacts as it can cause probelms in all systems
Psychosocial and financial impact on parents and families.
Often forced speration due to treatments, hard to bond. Also might be maternal complications
What are the long term costs of preterm?
- Recurrent hospitalisations
- Neurodevelopmental disabilities i.e cognition, motor dificits, sensory impairment, behaviour or psychology
- Chronic health issues
- Adulthood might be insulin resistance, diabetes etc
What is viability?
GA where a baby can be resus’d at delivery and survive without significant morbidity ~23 weeks
What determiens perivaibility?
- GA
- Use of corticosteroids
- Sex
- Infection / rupture of membranes
Essentially though its lung development and being in a tertiary care centre
What are two pathologies of periviabiltiy babes:
- Bronchopulmonary dysplasia
- Resp. distress syndrome