Biology Questions

What are the best to worst routes of exposure, in terms of teratogenicity?

Large molecular weight drugs that cannot cross the placenta include

o Babies born to mothers taking this during pregnancy have a 30 to 40% risk of developmental disability and 10% risk of birth defects o New guidance says that it must not be used in any girl or woman able to have children unless there is a pregnancy prevention programme (PPP) in place o There is no safe dose that can be used in pregnancy o In 2020 increasing realisation of lack of awareness of the risk - need for extra guidelines for prescriber and patient

Women aged 16 to 24 are _________ (more/less) likely to engage in binge drinking than older women, during their pregnancy

In Mendelian inheritance, the risk to future babies ______ (does/does not) alter in relation to the number of affected babies already born

the umbrella term for the range of preventable alcohol-related birth defects which are a direct result of prenatal alcohol exposure and it is used for those who are diagnosed with some, but not all of the symptoms of FAS

Possible mechanism of action as to how harm is caused include: • May be beneficial or harmless to the mothers but harmful or lethal to the embryo or the foetus• Time of exposure is critically important • Susceptibility may be genetically determined • It is usually dose dependent • Agents may be synergistic • A specific placental barrier does not exist • Risk may be altered by individual variation in drug pharmacokinetic metabolism

• Results from failure of the fusion of the caudal neural tube• The causes include chromosome abnormalities, single gene disorders, and teratogenic exposures • Cause is not known in most cases• Up to 70% can be prevented by mother taking folic acid supplements during pregnancy • How the folate works is unknown - likely to involve genes that regulate folate transport and metabolism • Established Risk Factors o History of previous affected pregnancy with same partner o Inadequate maternal intake of folic acid o Pre-gestational maternal diabeteso Valproic acid and carbamazepine

o Inheritable character that is caused by a change in the DNA sequence of a single gene o Genetically based malformation syndromes o More than 6000 known single gene disorders o Inherited recognisable patterns: autosomal dominant, autosomal recessive, sex-linkedo The risk to future babies does not alter in relation to the number of affected babies already born

What percentage of birth defect causes are genetic transmission?

What percentage of birth defect causes are radiation?

What percentage of congenital malformations are drugs and chemicals thought to account for?

There is usually a threshold dose, below which a teratogen has no observable effect

What is the background risk of congenital malformations in the babies of normal young, fit and healthy mothers?

o Interaction of a drug or chemical against a particular genetic background o Caused by a combination of factors - environmental and mutations in multiple geneso The degree of sensitivity is variable o Depends on the particular genetic constitutions of mother and foetus

o Alcohol is associated with increased risk of spontaneous abortion. o Maternal alcohol intake affects the behaviours of the child, and this is how it is picked up as the facial features often go unnoticed o Attention span and lower academic ability often noted only at school o It can be difficult to establish alcohol as a cause, as there are often many other contributory factors o Damage to the brain is often, though not always accompanied by distinct facial deformities, physical and emotional developmental problems, memory and attention deficits, a variety of cognitive and behavioural problems o Affected individuals are at risk of developing a range of secondary comorbidities, including mental illness and alcohol and drug addiction o Facial dysmorphology includes: short palpebral fissures, a thin upper lip vermillion and a smooth philtrum

Women aged 16 to 24 drink ______ (more/less) frequently than older women in pregnancy

What percentage of birth defect causes are infection?

The administration of this agent to the pregnant mother directly or indirectly causes structural or functional abnormalities in the foetus or later in the child after birth, which may not be apparent until later in life

This substance has both direct (maternal vasodilation and hypoxia) and indirect risks (maternal problems in placenta) to a growing foetus