Module 1.3 (Pregnancy & associated conditions) Flashcards
1
Q
What is pregnancy defined as?
A
- successful pregnancy is achieved after implantation of a fertilised egg in the uterine wall
- adequate attachment of embryo results in foetal growth
2
Q
How is a pregnancy detected?
A
- increased release of (hCG) human chorionic gonadotropin hormone
- urine pregnancy tests detect hCG to determine a positive or negative pregnancy
- followed up by GP for a formal hCG blood level
3
Q
What are some early signs of pregnancy?
A
- missed mestrual period
- breat tenderness and swellling
- nausea & vomitting
- fatigue
- slightly elevated body temperature
4
Q
What is the timing of exposure?
A
1st trimester (1-12 weeks post last menstrual period)
- up to 2 weeks
- weeks 3-8, major organ systems being formed
2nd trimester (4-6th month)
- cerebellum & urogenital system still forming
- growth & functional development
3rd trimester (6-9th month)
- specific effects (NSAIDs & pulmonary hypertension) (Beta blockers & hypoglycaemia)
Near term/ during labour
- adverse effects on labour or on neonate after delivery
5
Q
What does foetal drug exposure depend on?
A
- medication properties
- dose of medication
- route of administration
- IV or oral or inhaled or topical
- maternal pharmacokinetics
- clearance, volume of distribution, protein binding
- medication properties
- almost all cross by simple diffusion
- drugs with high MW >600-800 daltons tend not to cross eg. heparins or insulins
- lipid soluble medications have a higher affinity to cross the placenta
- basic drugs cross preferentially as pH of placenta < pH maternal blood e.g. pethidine
6
Q
How to go about medications in pregnancy?
A
- try non-medication treatments first
- avoid first trimester unless clinically indicated
- use as few medications as possible
- use the lowest effective dose for shortest period of time
- use “safest” medications in group
- use “older” medications without evidence of harm
- avoid newer medications with little info
7
Q
What are the TGA categories?
A
- Category A
- large numbers, no adverse human effects
- Category B
- limited numbers, no adverse human data
- B1- no adverse animal data
- B2- animal data lacking or inadequate
- B3- animal data shows damage, human significance unknown
- Category C
- caused or suspected of causing harmful effects WITHOUT causing malformation
- effects may be reversible
- Category D
- caused, suspected or expected to cause an increase in malformations or irreversible damage
- Category X
- high risk of permanent damage & should not be used
- e.g. thalidomide
8
Q
What are some issues associated with the TGA categories?
A
- A-X categorisation
- implies C is worse than B
- Clinical context
- no consideration for more or less significant conditions
- risk vs benefit
- ALL in category carry same risk
- valproate has significantly higher teratogenic potential than paroxetine
- but both in category D
- Pregnancy stage is not considered
- NSAIDs category C
- Dose, route not considered
- topical, single dose, short, long term use different considerations
- New drugs
- animal studies, never changes
9
Q
What questions must we consider?
A
- prospective or retrospective exposure (planning to have or already taken)
- identify drug, dose frequence, route and duration of exposure
- how many weeks pregnant when started drug?
- how many weeks now?
- taken drug in previous pregnancy?
- family history of malformations?
- age?
10
Q
What are some common pregnancy conditions?
A
- GORD
- vitamin supplementation
- nausea/ vomitting
- diabetes
- pre-existing diabetes
- gestational diabetes
- hypertension
- constipation in pregnancy
11
Q
What vitamin supplementation is required in pregnancy?
A
- folic acid
- present in some food (bread) but not enough
- dietary supplementation recommended from 12 weeks before conception and through the first trimester of pregnancy
- reduces risk of neural tube defects
- recommended dose: 500mcg daily
- 5mg dose for increased risk of NTD or certain medications e.g. antiepileptics
- iodine
- if not enough in diet
- used for health brain development in fetus
- contained in iodinised salt, bread & milk
- recommended dose: 150mcg
12
Q
What other vitamin supplementation are required in pregnancy? #2
A
- iron
- supplementation is based on dietary intake & Hb levels
- usually 100mg of elemental iron daily or BD
- increased incidence of constipation in pregnancy
- Vitamin D
- ensures adequate bone development & calcium absorption in neonate
- based on dietary intake & Hb levels
- supplementation should be started where colecalciferol levels are lower theb 50nmol/L
- usual dose range of 1000units to 2000 units
- Vitamin A
- limited evidence and may cause more harm than benefit
- high dose vitamin A may cause defects in infant
13
Q
Talk about nausea and vomitting in pregnancy?
A
- can occur in 80% of pregnancies, very common
- can be mild, moderate or severe
- mild, moderate
- manageable by lifestye or dietary changes
- avoid spicy foods & fatty foods
- identify & avoid triggers where possible
- ginger tablets
- manageable by lifestye or dietary changes
- moderate, severe
- may require medication to assist with symptoms
- hyperemesis gravidarum- medical emergency
- severe nausea/ vomitting
- can lead to hospitalisation due to dehydration and limited oral intake
14
Q
How is MILD OR MODERATE nausea and vomitting managed in pregnancy?
A
- Pyroxidine (vitamin B6) 50mg orally up to FOUR times a day or 200mg orally at night
- Add doxylamine (restavit) 12.5mg orally nocte, increase to 25mg nocte then add 12.5mg mane and afternoon as required
- Add another sedating antihistamine
- Promethazine (phenergan) (safe in 1st trimester) 10-25mg orally 3-4 times a day OR
- Dimenhydrinate (dramamine) 50mg orally 3-4 times a day
- Add either of the following if not improving
- Metocloperamide 10mg orally 3-4 times daily OR
- Prochlorperazine 5-10mg orally 2-3 times daily OR
- 25mg PR 1-2 times daily
15
Q
How is SEVERE, PERSISTENT OR RESISTANT nausea and vomitting managed in pregnancy?
A
- Ondansetron 4mg orally (tablet or wafer) 2 or 3 times a day- place on tongue & allow to dissolve
Consider changing regime to ANY of the following:
- Metocloperamide 10mg IV/IM q8hrs
- Prochlorperazine 12.5mg IM q8hrs
- Promethazine 12.5-25mg IM q4-6hrs
- Ondansetron 4mg IV/IM q8-12hrs
If sxs persist,
5. Prednisolone 50mg orally daily for 3 days, then reduce to 25mg at 3 days then reduce by 5mg as tolerated until resolved
- monitor BGL and consider prophylaxis with ranitidine 300mg nocte a day to prevent GI upset
24
Q
What antihypertensive therapy is used in pregnancy?
A
