KCP: Pre-Conception Counselling, Pregnancy and Prescribing Flashcards
What is a teratogen?
Anything a person is exposed to or ingests during pregnancy that’s known to cause fetal abnormalities
What is folic acid converted into by the body?
It is coverted by the body into folate. Also known as folacin or vitamin B9
What is folic acid required for?
Synthesis of purine and pyrimidine
Why are purines and pyrimidines required by an embryo?
They are involved in many things but particularly the conversion of amino acids required to make neuroepithelial cells in order to close the neural tube and prevent brain and CNS defects
What is the neural tube?
This is the proto brain and spine
Advised folic acid intake for women trying to conceive?
400μg daily when trying to conceive until 12 weeks pregnant
Safe levels of alcohol during pregnacy?
No safe levels of alcohol
More significant exposure causes foetal alcohol syndrome
What does foetal alcohol spectrum disorder effect?
- CNS
- Facial dysmorphism
What are the common features of facial dysmorphism caused by foetal alcohol spectrum disorder
- Low nasal bridge
- Smooth philtrum
- Thin upper lip
- Small palpebral fissures
Drugs that can effect foetal development and what they are used to treat
- Methotrexate (RA)
- Sodium valproate (Epilepsy)
- Angiotensin converting enzyme inhibitors ACEi (hypertension, heart failure & renal disease)
- NSAIDs
What is the action of methotrexate in causing foetal defects?
- DHF (dihydrofolate) is part of the process of purine and pyrimidine sythesis
- Methotrexate is a competative inhibitor of DHF
- Reduces cell devision
- Reduces amino acid sythesis
- Anatagonises action of folic acid
What is the advice regarding methotrexate?
- Should be off methotrexate for 3 months before conception
- Hydroxychloroquine and sulfasalazine and safe DMARDs
What are alternative DMARDs that a safe during pregnancy?
- Hydroxychloroquine
- Sulfasalazine
Effect of sodium valproate on foetuses
- Neural tube defects are associated with 1-2% of pregnancies
- Also associated with cadiac, oral and urogenital defects
Advice for sodium valproate prescription
Should not be prescribed to womean or child bearing age unless in a pregnancy prevention programme
Effects of ACEi/ARB in pregnancy
When should ACEi/ARB exposure be avoided?
2nd and 3rd trimester
When should NSAIDs be avoided?
Third trimester
Why do NSAIDs need to be avoided?
- Foetuses have a blood vessel called ductus areteriosus which allowing blood to pass form the pulmonary artery to the aorta therefore bypassing the lung
- This closes after birth and is kept open by protaglandin E (PGE) produced by the placenta
- NSAIDs inhibit PGE therefore causes early closing of the ductus areteriosus
- This leads to pulmonary hypertension and fetal hydrops
What is foetal hydrops?
Basically odema in a foetus
