Applied Embryology Flashcards
What are the most common anomalies?
Congenital heart defects
How many babies are affected by neural tube defects?
1 in 1,000
What is the prognosis for those with congenital heart defects?
6% die before their first birthday
What percentage of babies are born with birth defects?
2.2%
What is a teratogen?
An environmental exposure (such as a drug, substance or infection) to which the mother is exposed to during pregnancy which can result in birth defects in the foetus
What can teratogens lead to?
- May detrimentally affect the developing embryo/foetus in utero
- May lead to structural or functional abnormalities or even IUD
What effects can teratogens have on the developing foetus?
- Death
- Learning difficulties
- Sensory deficient
- Structural abnormalities
- Cancer
- IUGR or growth defects
- Neurodevelopmental / behavioural dysfunction
- Developmental delay
When can adverse effects occur in utero?
At any stage in the pregnancy
When do structural defects take place?
In the first trimester during organogenesis
When is the greatest risk of structural defects?
Between weeks 3 and 11
When are functional and growth defects most likely to occur?
After 12 weeks of gestation
Give examples of drug teratogens.
- Carbamazepine
- Phenytoin
- Tetracyclines
- Sodium valproate
- Diethylstilboesterol
- Thalidomide
- Alcohol
- Cigarette smoke
- Illegal drugs
- Retinoids
What is binge drinking?
When an individual drinks 5 or more units of alcohol on one occasion
When is binge drinking particularly harmful?
Around conception and in early pregnancy
What is heavy drinking often related to?
Unprotected sex which may lead to unplanned pregnancies and STIs
What is the classic triad for congenital rubella syndrome?
- Sensorineural deafness
- Eye abnormalities (especially retinopathy, cataract and microphthalmia)
- Congenital heart disease (especially pulmonary artery stenosis and patent ductus arteriosus)
What can varicella in a foetus lead to?
- Limb hypoplasia
- Skin scarring
- Eye defects
When does varicella pose the greatest risk to foetuses?
During the 2nd trimester
When does cardiac development take place?
Between weeks 3 and 6
Give examples of drugs that can interfere with cardiac development.
- Warfarin
- Lithium
How is the link between teratogens and foetal abnormalities made?
- Clinicians noticing patterns such as rubella and thalidomide
- Epidemiology/ ecological studies
What can opiate medications given for maternal pain during labour cause in the baby?
- Respiratory depression
- Effect on brain
- Effect on skeleton
- Growth restriction
Who is preconception counselling vital for?
- Epileptics
- Diabetics
- Women on anticoagulants
- Women with congenital anomalies
- Women on anti-hypertensives
When should women start taking folic acid?
Around 3 months before they aim to fall pregnant
