A 30-year-old female, status post adrenalectomy for Cushing's syndrome, currently taking prednisone 5 mg once daily, is 8 weeks pregnant. How should she be managed during pregnancy?

Management of Pregnant Patient Post-Adrenalectomy for Cushing's Syndrome on Prednisone

Switch from prednisone to hydrocortisone immediately, as hydrocortisone is the preferred glucocorticoid during pregnancy because it is metabolized by the placenta and minimizes fetal exposure. 1

Immediate Medication Change

Your patient requires a glucocorticoid switch because prednisone crosses the placenta more readily than hydrocortisone. The 2016 Endocrine Society guidelines explicitly recommend using hydrocortisone over prednisone or prednisolone in pregnant women with adrenal insufficiency and recommend against dexamethasone because it is not inactivated in the placenta 1.

• Convert prednisone 5 mg daily to hydrocortisone 20 mg daily (prednisone 5 mg ≈ hydrocortisone 20 mg)
• Divide hydrocortisone into 2-3 doses: typically 10 mg upon waking, 5-10 mg at midday, and 5 mg in early evening to mimic physiological cortisol rhythm 1
• Prednisone and prednisolone allow only 10% of maternal dose to reach the fetus, but hydrocortisone is even safer with greater placental metabolism 2

Monitoring Throughout Pregnancy

Schedule clinical assessments at least once per trimester to evaluate for signs of glucocorticoid over- or under-replacement 1:

Signs to Monitor:

• Under-replacement: fatigue, postural hypotension, inadequate weight gain, nausea
• Over-replacement: excessive weight gain, hypertension, hyperglycemia
• Blood pressure at each visit
• Weight gain trajectory
• Random glucose or HbA1c if concerns for hyperglycemia arise

Dose Adjustment Strategy

Plan to increase hydrocortisone dose by 20-40% starting at 24 weeks gestation (third trimester), as free cortisol levels increase significantly from week 22 onward in normal pregnancy 1. This physiological increase is due to rising cortisol-binding globulin (CBG) levels and increased free cortisol requirements.

• At 24 weeks: increase from 20 mg to 25-30 mg daily (divided doses)
• Adjust based on clinical symptoms—some patients may need the full 40% increase
• The evidence notes that adrenal crisis from insufficient dose adjustment during pregnancy has been reported 1

Important Caveat:

While the guidelines suggest dose increases "based on individual clinical course," the physiological data strongly support proactive dose escalation in the third trimester rather than waiting for symptoms of insufficiency to develop.

Labor and Delivery Planning

Administer stress-dose hydrocortisone during active labor equivalent to major surgical stress 1:

• 100 mg hydrocortisone IV bolus at onset of active labor
• Followed by continuous IV infusion of 200 mg hydrocortisone over 24 hours (or 50 mg IV/IM every 6 hours)
• Continue stress dosing until delivery is complete and patient is stable
• Taper back to maintenance dose over 24-48 hours postpartum

This recommendation carries the highest strength (1QQEE) in the guidelines because inadequate glucocorticoid coverage during the physiological stress of labor can precipitate adrenal crisis 1.

Postpartum Management

• Return to pre-pregnancy hydrocortisone dose (20 mg daily) within 1-2 days after delivery, as cortisol levels normalize rapidly postpartum 1
• Hydrocortisone is excreted minimally into breast milk; breastfeeding is safe 2
• To further minimize infant exposure, advise avoiding breastfeeding during the first 4 hours after taking hydrocortisone when milk concentrations peak 2

Patient Education Essentials

Provide written instructions on:

• Stress dosing: double the daily dose for minor illness (fever, infection requiring antibiotics) until recovered
• Emergency injectable hydrocortisone: prescribe 100 mg IM hydrocortisone for home use in case of vomiting/inability to take oral medication
• Medical alert identification: ensure she wears medical alert bracelet indicating adrenal insufficiency
• Signs of adrenal crisis: severe weakness, confusion, abdominal pain, vomiting—requires immediate emergency care

Safety Considerations for Mother and Fetus

The evidence is reassuring: glucocorticoids during pregnancy have no additional risk for mother and child when appropriately dosed 2. Prednisone and methylprednisolone are FDA pregnancy category B with no evidence of teratogenicity in humans at physiological replacement doses 2. However, hydrocortisone remains preferred due to superior placental metabolism.

High-dose glucocorticoids have been associated with low birth weight in humans, but this is not a concern at physiological replacement doses 2. The greater risk is inadequate replacement leading to maternal adrenal crisis, which poses serious risks to both mother and fetus 1.

Key Pitfall to Avoid

Do not continue prednisone throughout pregnancy simply because the patient is currently stable on it. The placental transfer difference between prednisone and hydrocortisone, while modest at replacement doses, becomes clinically significant when doses need to be increased in the third trimester. The guideline recommendation is explicit and evidence-based 1.