Obstetrics Flashcards
Define teratogenesis
Dysgenesis of fetal organs structurally or functionally.
What day range is the embryo most vulnerable to teratogenesis? why?
Embryo is most vulnerable within days 18-55 as this is when cells differentiate and major organs are formed.
What can happen after the “sensitive” embryo phase? Give example of organs effected.
Congenital malformations can occur at day 56 of birth. Organs such as the cerebral cortex and renal glomeruli continue to develop and are susceptible to damage!
The incidence of Tetatogenecity is …
Usually dose-dependent.
State 4 roles of the placenta
- Endocrine function
- Immunity
- Excretion
- Nutrition
State 6 major changes that occur during gestation
1) Respiratory rate increases
2) Cardiovascular output increases
3) Plasma volume increases
4) Blood flow to the skin increases
5) GFR increases by 50% by the end of first trimester
6) Alterations in metabolic enzymes in the liver
how do most drugs cross the placenta, and what qualities of a drug make it able to pass across the placenta. What qualities render it unable?
99% of drugs cross the placenta by diffusion
Drugs that cross the placenta are non-ionised, lipid soluble.
Drugs that tend not to cross are polar, ionised , and have high molecular weight
what four key ways can we minimise risk to baby
Safe practices of minimising risk to foetus Non-drug treatment Avoid in first trimester Avoid teratogens Lowest effective dose
In what cases do we continue therapy of pregnant women?
- DVT/PE
- Diabetes
- HIV
- Hypertension
- Asthma
- Transplant patients
- Epilepsy
State four key benefits of baby’s receiving breast milk
- less chance of diarrhoea and vomiting
- Infections
- constipation
- Eczema
Benefits for the mother of giving breast milk?
Benefits of mother of giving breast milk
- Reduces risk of breast and ovarian cancer
- Burns 500 calories per day
What are the 3 criteria for drugs that are SAFE in pregnancy?
Drugs regarded as safe in pregnancy are:
- Highly protein protein bound
- Drugs which shorter half-life
- Drugs with a low plasma-to-milk ratio
The lower the ratio = less drug reaches the milk
What four factors are needed before we prescribe a drug for a mother who has a newborn kid?
- Need for drug
- Age & Maturity of the baby
- Volume of breast milk being taken
- Safety of the drug
What kind of drugs enter breast milk?
Drugs that pass into breastmilk
- Drugs with low plasma protein binding
- Low molecular weight
- High lipophilicity
- Cationic drugs
What factors excluding Mw/Charge/Lipophilicity affect drug diffusion into breast milk?
- Maternal Pharmacokinetics
- Composition of blood verses milk
- Characteristics of the drug
