Asthma in Pregnancy

Clinical Description

Reversible airway inflammation and bronchoconstriction.

Signs and Symptoms

• Asthma is unpredictable in pregnancy: 1/3 of women report improvement, 1/3 remain the same, and 1/3 worsen.
• Trigger (often viral), chest tightness, shortness of breath, cough, wheezing, tachypnea

Investigations

• Peak flow meter or spirometry, pulse oximetry

Treatment

• Avoid triggers and use inhaled corticosteroids to decrease underlying inflammation (for detailed information refer to O & G protocols and guidelines and MSTG respiratory conditions section).
• Antenatal clinics visit monthly if on regular medication.
• Avoid GERD in 3rd trimester by using Proton Pump Inhibitor or H2 blocker
• Peak flow meter EVERY 12HRS (first thing in the morning and 12 hrs later) if available
• For mild - moderate persistent asthma: salbutamol inhaler 1-2 puffs EVERY 8HRS or corticosteroid inhaler (i.e., beclomethasone)
• For acute and/or severe exacerbations:
• Admit to HDU
• O2 therapy to keep SaO2 >95%
• inhaled bronchodilator (salbutamol, ipromium bromide and normal saline) through a nebulizer or spacer every 10-20 min until improvement seen
• IV fluids
• IV Aminophylline 250 mg over 10 min or MGSo4 2g stat
• Sit up
• 4-hourly fetal monitoring
• Systemic steroids (i.e. hydrocortisone or prednisone IV) for up to 5-7 days
• Continuously assess response to treatment, complete response is resolution of symptoms and PEFR>80%
• Incomplete response is continuation of symptoms PEFR<80% personal best
• Urgent intervention required when PEFR <50% personal best
• Indication for intubation and ventilation: inability to maintain respiratory drive, worsening hypercapnia, respiratory acidosis, confusion and inability to maintain SpO2> 95% despite high flow oxygen

Intrapartum management

• Refer if at the health centre
• continue regular inhaler prn
• Use of IV hydrocortisone if patient has been on oral steroids >7.5mg/day for >2 weeks
• 4-hourly fetal monitoring
• Misoprostol if indication for labour induction
• Oxytocin if PPH
• Avoid use of PGF2 and Ergometrine