Med in Preggo

• Placenta


  Lipophilic unionized small mw drugs can cross the placenta and as the placenta thins the drug exposure increases
• Foetus is at risk


  When drugs cross the placenta
• Drugs are <0.2% cause of all live birth abnormalities
• Abnormalities may be detected at birth or take years to identify
• Types of potential adverse effects

  • Neurodevelopmental/ behavioural effects
  • Foetal malformation
  • Intra-uterine growth retardation
  • Premature birth and still birth
  • Obstetric complications
  • Neonatal s/e
  • Ovarian cancer
• Neurodevelopmental/ behavioural effects


  • sodium valproate, phenytoin, alcohol
• Foetal malformation


  • isotretinoin (cleft palate, external ear/ eye/ thymus and parathyroid abnormalities (no eye ball), ↓ septum (brain) growth)
• Intra-uterine growth retardation


  • cocaine
• Premature birth and still birth

  • theophylline
• Obstetric complications


  • Aspirin, NSAIDs that are taken closer to term
• Neonatal s/e


  • TCS, SSRI
• Ovarian cancer


  • diethylstilbesterol
• Teratogens


  • ACE inhibitors
  • sodium valproate
  • hypoglycaemics
  • methotrexate
  • warfarin
• Stage of pregnancy


  Influences choice of medicine
• Drug dosage


  No safe dosage publications
• Frequency of ingestion


  Increased drug accumulation which can lead to toxicity if it crosses the placenta
• Mother's nutritional status


  Folic acid? Vitamin D 10 mcg daily?
• Genetics


  Foetal hydantoin syndrome
• Prescribing principles


  • Consider the possibility of pregnancy in all women of childbearing age
  • Use non-pharmacological treatments where possible
  • Avoid medicines use as much as possible in pregnancy
  • Where drugs are needed, use the one with the best-known safety profile
  • Use the lowest effective dose for the shortest possible time, where appropriate
  • Long term conditions – medication review prior to pregnancy
  • Compliance important – drug may be less harmful than condition
  • Close monitoring may be required
  • Consider route of administration
• Folic acid


  Neural tube defect, Women at a normal risk of 400 mcg daily pre-conception up to 12-week preggo, Women at HIGH risk: 5mg daily up to the 12th week preggo or until birth if a woman with thalassaemia trait, Folic is synthetic form which is highly bioavailable and stable unlike folate (natural form) found in greens
• Access to balanced information vital
• Indication


  • Asthma (8%)
  • Diabetes (5%)
  • Hypertension (10%)
  • Epilepsy (1%)
  • Depression (20%)
• Asthma


  • One SABA, LABA
  • One inhaled corticosteroid (oral are continued → benefit>risk(oral cleft))
  • Oral and IV theophylline – TDM
  • Leukotriene receptor antagonist (only if necessary)
• Asthma complications


  hypertensive disorders, intrauterine growth retardation, preterm labour and delivery
• Maximize lung fxn → ↓ risk of an asthma attack
• Diabetes


  • Monitor (Fasting, 1hr post meal & bedtime daily, Ideal HbA1C < 48mmol/moL (6.5%), Fasting: 5.33mmol/litre, 1hr post meal: 7.88mmol/litre (in general keep glucose >4 mmol/litre))
  • Diet and exercise
  • Metformin (for T2D , also can be an adjunct or alternative to insulin)
  • Insulin
• Diabetes complications


  Obstetric: miscarriage, pre-eclampsia, pre-term labour, Foetal / neonatal complications: stillbirth, macrosomia (large baby), birth injury
• Substitution for any previously used oral anti-diabetic/ metformin is CI
• Nausea/vomiting disrupts eating (change time/dose of insulin)
• Lower threshold for glycosuria
• Co-prescribed meds for diabetes

  • Folic acid 5 mg until 12 weeks of gestation
  • Aspirin 75mg started in all ladies w/ pre-existing T1/T2 diabetes or at risk of pre-eclampsia
• Hypertension


  • Chronic Hypertension
  • Preggo induced hypertension
  • Pre-eclampsia
• Hypertension target


  <135/85 mmHg / if chronic hypertension <140/90 mmHg if too low → fetal growth affected
• Hypertension 1st line


  • Labetalol (Lic1) –100mg BD
• Hypertension 2nd line


  • Nifedipine
• Avoid ACE: PRIL, ARB: SARTAN, Diuretics: Furosemide (↓ plasma), Chlorothiazide – even in breastfeeding
• Hypertension complications


  Risk of gestational diabetes, Effect of proteinuria (Liver damage, Placenta rupture, Kidney damage)
• Other hypertension meds


  • Methyldopa(lic)– 250mg BD/TDS
  • Aspirin 75 mg
• Avoid methyldopa in pregnancy with depression
• Two days post birth- switch back to normal ACE/ARBs , avoid risk of depression