Chronic Conditions in Pregnancy

Hypothyroidism

  • Levothyroxine dose needs to be increased during pregnancy, usually by at least 25-50 mcg (30-50%)
  • Treatment is titrated based on the TSH level, aiming for a low-normal TSH level

Hypertension

  • Women with existing hypertension may need changes to their medications
  • Medications that should be stopped as they may cause congenital abnormalities:
    • ACE inhibitors
    • ARBs
    • Thiazide and thiazide-like diuretics
  • Medications that are not known to be harmful:
    • Labetalol (other beta blockers may have adverse effects)
    • CCBs
    • Alpha blockers

Epilepsy

  • Women with epilepsy should take folic acid 5mg daily from before conception to reduce the risk of neural tube defects
  • Ideally, epilepsy should be controlled with a single anti-epileptic drug before becoming pregnant
  • Levetiracetam, lamotrigine and carbamazepine are the safer anti-epileptic medication in pregnancy
  • Sodium valproate is avoided as it causes neural tube defects and developmental delay
  • Phenytoin is avoided as it causes cleft lip and palate

Rheumatoid arthritis

  • Ideally, rheumatoid arthritis should be well controlled for at least three months before becoming pregnant
  • Often the symptoms of rheumatoid arthritis will improve during pregnancy, and may flare up after delivery
  • The treatment regime may need to be altered by a specialist rheumatologist before and during pregnancy:
    • Methotrexate is contraindicated, and is teratogenic, causing miscarriage and congenital abnormalities
    • Hydroxychloroquine is considered safe during pregnancy and is often the first-line choice
    • Sulfasalazine is considered safe during pregnancy
    • Corticosteroids may be used during flare-ups

Diabetes

Effect of pregnancy on diabetes

  • Increases insulin requirements
  • N+V can precipitate DKA
  • Ketosis more common
  • Diabetic retinopathy worsents especially after rapid control of diabetes
  • Diabetic nephropathy can worsen

Management

  • Pre-pregnancy counselling
    • HbA1c 48 mmol/mol
    • Stop embryopathic medication
    • High dose folic acid 5mg (3 months before conception to 12 weeks of pregnancy)
  • Antenatal management
    • Screen for complications
    • Counsel about shoulder dystocia risk
    • Deliver by 38+6/40 (type 1 and 2), earlier if complications
  • Post-natal
    • Type 2 - revert to pre-pregnancy treatment
    • Type 1 - pre-pregnancy insulin doses, breastfeeding causes hypoglycaemia

Cardiac problems in pregnancy

  • Cardiac system works harder during pregnancy
  • Pregnancy associated with 3-4x increased risk of MI
  • Peri-partum cardiomyopathy associated with orthopnoea