Disorders of Pregnancy and Parturition Flashcards
What is pre-eclampsia?
a disorder of pregnancy associated with new-onset hypertension
Describe the pathophysiology of pre-eclampsia.
Changes in the placental structure- there is a failure of
conversion of spiral arteries.
EVT invasion of maternal spiral arteries is limited to the decidual layer and are not extensively
remodelled within the myometrium -thus this restricts placental perfusion.
- Vessels retain spiral structure– high resistance
- Limited perfusion of the maternal blood spaces, and therefore the exchange between the maternal blood and trophoblast is limited.
When does pre-eclampsia typically occur?
20 weeks of gestation (late second trimester)
What is the typical blood pressure reading of pre-eclampsia patients, how does it change from the normal 120/80?
Systolic 140mmHg and/or 90mmHg Diastolic
What are 3 symptoms of pre-eclampsia?
Frontal headache presents within 40% of pre-eclampsia cases
Oedema common however not discriminatory
Abdominal pain (15% of severe pre-eclampsia patients)
Visual disturbances, seizures and breathlessness associated with severe pre-eclampsia
Where is pre-eclampsia more common globally?
Africa and Asia
What are the subtypes of pre-eclampsia?
Early onset
- <34 weeks
- associated with foetal and maternal symptoms
- changes in placental structure
Late onset
- >34 weeks
- more common
- mostly maternal symptoms
- foetus generally ok
- less overt/ no placental changes
What maternal risk factors pre-dispose pre-eclampsia?
previous pregnancy with pre-eclampsia
BMI >30 (especially >35)
family history
increased maternal age (greater than 40, less than 20?)
gestational hypertension or previous hypertension
pre-existing conditions: diabetes, PCOS, renal disease, sub-fertility, autoimmune disease
non-natural cycle IVF?
What are the risks to the foetus and mother?
Mother: damage to kidneys, liver, brain, and other organ system
- possible progression to eclampsia (seizures, loss of consciousness)
Placental abruption (separation of the placenta from the endometrium)
foetus: reduced foetal growth, preterm birth, pregnancy loss/ stillbirth
What are PLGF and Flt1?
PLGF: Placental Growth Factor
VEGF related, pro-angiogenic factor released in large amounts by the placenta.
Flt1 (soluble VEGFR1)
Soluble receptor for VEGF-like factors which binds soluble angiogenic factors to limit their bioavailabliltiy.
How is Flt1 and pre-eclampsia linked?
excess production of Flt-1 by distressed placenta leads to reduction of available pro-angiogenic factors in maternal circulation, resulting in endothelial dysfunction.
What is the difference between a healthy and pre-eclampsia placenta linking to Flt1 and PLGF?
Healthy placenta
Releases PLGF and VEGF into the maternal circulation. These growth factors bind receptors on the endothelial surface to promote vasodilation, anti-coagulation and ‘healthy’ maternal endothelial cells.
Pre-eclampsia placenta
Releases sFLT1, which acts as a sponge – mopping up PLGF and VEGF and stopping them binding to the endothelial surface receptors. In the absence of these signals, the endothelial cells become dysfunctional.
How do you manage pre-eclampsia?
If less than 34 weeks, preferable to try and maintain the pregnancy if possible for benefit of the foetus
If more than 37 weeks, delivery preferably
Anti-hypertensive therapies
Corticosteroids for less than 34 weeks to promote foetal lung development before delivery
How do you prevent pre-eclampsia?
Weight loss
Exercise throughout pregnancy (works independent of BMI)
Low-dose aspirin (from 11-14 weeks) for high risk groups- may only prevent early onset
What are the long-term impacts of pre-eclampsia on maternal health?
Elevated risk of cardiovascular disease, type 2 diabetes and renal disease after pre-eclampsia
roughly 1/8 risk of having pre-eclampsia in next pregnancy (greater if early onset)
