Pregnancy & associated conditions 3

Question 1

What is pregnancy defined as?

Answer 1

• successful pregnancy is achieved after implantation of a fertilised egg in the uterine wall
  
  • adequate attachment of embryo results in foetal growth

Question 2

How is a pregnancy detected?

Answer 2

• increased release of (hCG) human chorio gonadotropin hormone
  
  • urine pregnancy tests detect hCG to determine a positive or negative pregnancy
  • followed up by GP for a formal hCG blood level

Question 3

What are some early signs of pregnancy?

Answer 3

• missed mestrual period
• breat tenderness and swellling
• nausea & vomitting
• fatigue
• slightly elevated body temperature

Question 4

What is the timing of exposure?

Answer 4

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

Question 5

What does foetal drug exposure depend on?

Answer 5

• 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

Question 6

How to go about medications in pregnancy?

Answer 6

• 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

Question 7

What are the TGA categories?

Answer 7

• 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 of unsuspected 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

Question 8

What are some issues associated with the TGA categories?

Answer 8

• 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

Question 9

What questions must we consider?

Answer 9

• prospective or retrospective exposure
• 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?

Question 10

What are some common pregnancy conditions?

Answer 10

• GORD
• vitamin supplementation
• nausea/ vomitting
• diabetes
  
  • pre-existing diabetes
  • gestational diabetes
• hypertension
• constipation in pregnancy

Question 11

What vitamin supplementation is required in pregnancy?

Answer 11

• 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

Question 12

What other vitamin supplementation are required in pregnancy? #2

Answer 12

• 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

Question 13

Talk about nausea and vomitting in pregnancy?

Answer 13

• 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
• 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

Question 14

How is MILD OR MODERATE nausea and vomitting managed in pregnancy?

Answer 14

1. Pyroxidine (vitamin B6) 50mg orally up to FOUR times a day or 200mg orally at night
2. Add doxylamine (restavit) 12.5mg orally nocte, increase to 25mg nocte then add 12.5mg mane and afternoon as required
3. Add another sedating antihistamine
   
   1. Promethazine (phenergan) (safe in 1st trimester) 10-25mg orally 3-4 times a day OR
   2. Dimenhydrinate (dramamine) 50mg orally 3-4 times a day
4. Add either of the following if not improving
   
   1. Metocloperamide 10mg orally 3-4 times daily OR
   2. Prochlorperazine 5-10mg orally 2-3 times daily OR
   3. 25mg PR 1-2 times daily

Question 15

How is SEVERE, PERSISTENT OR RESISTANT nausea and vomitting managed in pregnancy?

Answer 15

1. 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:

1. Metocloperamide 10mg IV/IM q8hrs
2. Prochlorperazine 12.5mg IM q8hrs
3. Promethazine 12.5-25mg IM q4-6hrs
4. 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

Question 16

When does GORD normally occur in pregnancy?

Answer 16

• common in 2nd & 3rd trimester
• due to relaxation of oesophageal sphincter and delayed gastric emptying
• get build up of acid in women

Question 17

What dietary modifications can be helpful in GORD?

Answer 17

• reduce meal sizes to avoid discomfort
• avoid lying down immediately after eating
• avoid fatty & spicy foods
• drink water at least half an hour before a meal
• sleep elevated
• try these 1st to avoid medication therapy where possible

Question 18

How is GORD managed with medication?

Answer 18

• Antacids- calcium carbonate products, (gaviscon)
  
  • minimises acid in gut & reflux
• H2 receptor antagonists- ranitidine 150mg BD
  
  • reduces amount of acid developed
• PPIs
  
  • omeprazole 20-40mg daily
  • esomeprazole 20-40 daily

Question 19

How does pre- existing diabetes effect pregnancy and baby?

Answer 19

• glucose control is imperative for adequate foetal growth
• increased risk of foetal macrosomia
  
  • >4kg, larger than normal infant
  • risk to baby & mother
• neonatal hypoglycaemia at birth
• treatment of choice
  
  • insulin- first line
  • bolus and basal insulin therapy recommended
• metformin is used in uncontrolled patients and to assist with weight loss & decreased incidence of hypertension
• increased glucose, increased uptake by infant

Question 20

What are the risk factors for gestational diabetes?

Answer 20

• Previous GDM
• Ethnicity: Asian (including Indian), Aboriginal, Pacific Islander, Maori, Middle Eastern, non-white African
• Maternal age > 40 yrs n Family history of DM
• Obesity, especially if BMI > 35kg/m²
• Hypertension prior to 20 weeks n Previous macrosomia (baby with birth weight more than 4000g)
• History of unexplained stillbirth
• Previous baby with congenital abnormalities
• Polycystic ovarian syndrome
• Medications: corticosteroids, antipsychotics

Question 21

How is gestational diabetes diagnosed or tested?

Answer 21

• Oral Glucose Tolerance Test
  
  • Load of 75g of glucose given to measure body’s response to glucose
  • Blood sugar levels taken at fasting, 1 hour and 2 hours post glucose load
• Diagnostic criteria for GDM
  
  • fasting venous PG >= 5.1mmol/L
  • 1 hour venous PG>=10.0mmol/L
  • 2 hour venous PG>=8.5mmol/L
  • the diagnosis of GDM is made if one or more of the value is abnormal

Question 22

How is gestational diabetes mellitus managed?

Answer 22

• diet control
  
  • minimuse glucose & carbohydrate intake to reduce blood glucose level
• if unsuccessful insulin is medication of choice
• metformin used only under specialist advice

Question 23

What is pre- eclampsia?

Answer 23

• unique to human pregnancy
• due to high blood pressure
• A multi-system disorder that can affect both mother and baby
• Usual manifestation is;
  
  • NEW onset hypertension AFTER 20th week of pregnancy
  • Systolic ≥140mmHg/Diastolic ≥90mmHg plus
  • +
• Significant proteinuria:
• Spot urine protein/creatinine ratio (PCR) of ≥30mg/mmol
• Risks to infant
  
  • Placental abruption
  • Severe growth restriction
  • Pre-term delivery
  • Stillbirth
• Eclampsia – pre-eclampsia with seizures present

Question 24

What antihypertensive therapy is used in pregnancy?

Answer 24

Question 25

What therapy is antihypertensive therapy is contraindicated in pregnancy?

Answer 25

• ACE inhibitors
• ARBs
• causes neonatal renal failure

Question 26

How is constipation managed in pregnancy?

Answer 26

• identify underlying cause
  
  • •Dietary Habits •Physical Inactivity •Dehydration •Bowel Habits •Medications •Disease States
• non pharmacoogical changes
  
  • •Diet and Lifestyle •Increased Fibre •Adequate Fluid Intake •Increased activity •Response to defecation urge
• pharmacological management
  
  • •Bulk Forming Laxatives •Osmotic Laxatives •Stimulant Laxatives •Stool Softener •Prokinetic Medications

Question 27

What laxatives can be used in pregnancy?

Answer 27

• Bulk Forming Laxatives
  
  • Psyllium husk, isphaghula, wheat
  • Absorb water in the bowel and increase feacal bulk and stimulate persitaltic activity
  • slow acting
• Osmotic Laxatives
  
  • Lactulose, sorbitol, glycerol, macrogol
  • Draw water into the bowel and allow for stimulation of peristaltic activity
• Stool Softeners
  
  • Docusate, liquid paraffin, poloxamer
  • Soften stool and increase ability to pass faeces
• Stimulant laxatives: AVOID IN PREGNANCY
  
  • senna, bisacodyl