INFORMATION FOR HEALTH PROFESSIONALS

For information about medications in pregnancy, I recommend a comprehensive textbook such as: Drugs in Pregnancy and Lactation, 2015, 10th edition: Gerald G Briggs and Roger K Freeman. Lippincott Williams & Wilkins Publishers.

Mothersafe; the telephone and in person teratology service run from RHW is an excellent resource for drugs and exposures advice.

Phone: 9382 6539 (Sydney Metropolitan Area)
Phone: 1800 647 848 (Non-Metropolitan Area)
Alternatively, the in-depth answers on Micromedex database are very helpful.

MIMS and the A,B,C,D,X categories are not adequate for counselling individual patients

• Thyroid function in early pregnancy
• Universal screening is not recommended but is often performed
• For women with no personal or family history of thyroid disease, an estimate of TSH between 8-10 weeks gestation should be interpreted based on individual laboratory normal ranges
• Prior to 8 weeks, the normal ranges are closer to non-pregnant levels ie TSH does not fall into the pregnant range immediately.
• If an abnormal TSH is detected, initial management should follow this algorithim. Subsequent management will depend on individual counselling.

Assuming a normal range for 8-14 weeks pregnancy of 0.5-2.5Iu/L

• Women with pre-existing thyroid disease:
  • Hypothyroid:
    • Check FT3, FT4 and TSH at 7-8 weeks gestation and arrange an appointment around this time
    • An increase in thyroxine dose is required for the majority of women
  • Thyrotoxicosis
    • Avoid radio-iodine for 6 months prior to pregnancy
    • Check free T4, free T3 and TSH in early pregnancy and refer within 2-3 weeks.

• Normal BP in pregnancy is less than 140/90 mm Hg and often much lower
• A manual sphygmomanometer should be used to measure BP in pregnancy as automated monitors are less reliable
• New onset hypertension before 20 weeks gestation is almost always chronic hypertension or white coat hypertension
• New onset hypertension after 20 weeks gestation may be either chronic hypertension or a pregnancy related form of hypertension; either gestational hypertension or pre-eclampsia
• For women with pre-existing hypertension prior to pregnancy:
  • Refer for preconceptual counselling to set up a management plan for pregnancy and breastfeeding
  • Cease ACEI or angiotensin receptor blockers and diuretics as soon as pregnancy is confirmed
  • Other antihypertensive agents ie beta blockers, calcium antagonists, methyldopa, prazosin, hydralazine may be continued if required but seek specialist advice if needed
  • Arrange review within 2-4 weeks
• After 20 weeks, all women with BP >140/90 mm Hg need prompt assessment
  • Check urine dipstick; if proteinuria ≥2+, refer for urgent assessment (within 24 hours)
  • Otherwise: check FBC, UEC, LFT, urate, urine protein:creatinine ratio and refer within 1 week
  • Consider commencing antihypertensive treatment whilst awaiting assessment
• Gestational hypertension and pre-eclampsia can occur for the first time post-partum
  • If BP >140/90 mm Hg within 6 weeks of pregnancy, consider antihypertensive treatment and refer if not settling

Refer for preconceptual counselling to set up a management plan for pregnancy and breastfeeding

• Pregnancy is associated with a significantly increased risk of thromboembolism
• Chronic anticoagulation
  • All woman on chronic anticoagulation therapy will need to continue treatment
  • Cease warfarin and NOACs (rivaroxaban, epixaban, dabigatran) as soon possible after confirmation of pregnancy
  • Commence therapeutic LMWH eg enoxaparin 1mg/kg bd
  • Refer for specialist advice as soon as possible
• Women with a past history of venous or arterial thromboembolic events eg stroke, TIA
  • Refer for specialist advice
  • If in doubt, especially with recurrent episodes, or if referral is delayed, consider commencing prophylactic LMWH eg enoxaparin 40mg sc daily ( VTE) or aspirin 100mg nocte (arterial)
• Women with known thrombophilia or family history of significant thromboembolism
  • Refer for specialist advice , ideally pre-conception

• Nausea and vomiting that improves with eating is common in pregnancy
• Encourage any intake desired but ensure adequate fluids (not necessarily water)
• Consider simple treatments tabled below

• More severe cases of nausea and vomiting in pregnancy may be associated with dehydration, weight loss and electrolyte disturbances
• Women are often depressed and overwhelmed by this condition but it is not psychosomatic
• High recurrence risk
• Refer for preconceptual counselling to set up a management plan for early pregnancy
• Commence treatment as above
• Add ondansetron 4mg tablets bd (6-am and 1-2pm)
• Add doxylamine 6.25-25 mg nocte
• Treat constipation aggressively
• Refer early for specialist advice

Pre-existing Type 1, Type 2, Insulin resistance and carbohydrate intolerance

• Refer for pre-conception counselling and at 6-8 weeks once pregnancy is confirmed
• Aim for HbA!C < 6-7% prior to pregnancy
• Recommend high dose folate 5mg/day
• Tight blood sugar control is required during the first trimester to reduce the risk of congenital malformation during the critical first 10-12 weeks of pregnancy
• Continue usual treatment including oral hypoglycemics until pregnancy is confirmed but cease at time of positive pregnancy test in all except those with Type 2 diabetes on metformin
• Most women with pre-existing type 1 or 2 will need insulin in pregnancy

Previous gestational diabetes

• These women have a 70-80% risk of recurrence, often earlier in their pregnancy
• Counsel regarding healthy eating [http://kemh.health.wa.gov.au/brochures/consumers/wnhs0560.pdf] , appropriate weight gain targets and regular exercise
• Consider intermittent home BGL monitoring (early morning before breakfast and 1 or 2 hours post prandial) from early pregnancy as an alternative to OGTT if high risk
  • Target BGL: early morning before breakfast <5.0 and post prandial 1 hour <8.0 or 2 hours <7.0 mmol/L
  • If abnormal, assume recurrent GDM and refer (without OGTT)
• OGTT to be performed at 12-14 weeks and if normal, repeated at 26 weeks
  • Abnormal if F ≥5.0 mmol/l
  • 1 hr ≥10.0 mmol/l
  • 2 hr ≥8.5 mmol/l
• Refer promptly to diabetes educator and A/Prof Lowe once the diagnosis is confirmed