Asthma In Pregnancy

Clinical description

Asthma occurs when there is reversible bronchoconstriction and affects 4-12% of pregnancies.

It is associated with increased risk of mortality, preeclampsia, preterm delivery (PTD) and low birth weight.

Asthma is unpredictable in pregnancy: 1/3 of women report improvement, 1/3 remain the same, and 1/3 worsen.

Classificatio Persistent Intermittent n Mild Moderate Severe Symptoms ≤ 2 days/wk > 2 days/wk Daily Throughout the day but not daily Night time ≤ 2 3-4 >1 time/week but Often 7 times/week awakenings times/month times/month not nightly Short acting ≤ 2 days/wk > 2 days/wk Daily Several times/day beta 2 agonist but not daily use for and not > 1 symptom time on any control day Interference None Minor Some limitation Extremely limited with normal limitation activity Lung • Normal • FEV1 > • FEV1 60-79% • FEV1 < 60% function FEV1 80% predicted predicted between predicted • FEV1/FVC • FEV1/FVC reduced exacerbation • FEV1/FV reduced by ≤ by >5% s C normal 5% 80% predicted normal

Signs and symptoms

History/ExamTrigger (often viral), chest tightness, shortness of breath; cough, wheezing, decreased pulse ox InvestigationsPeak flow meter or spirometry, pulse oximetry

Treatment

Avoid triggers and use inhaled corticosteroids to decrease underlying inflammation

• Antenatal clinic visit monthly if on regular meds
• Peak flow meter BD (first thing in the morning and 12 hrs later) if available
• Avoid allergens and tobacco
• Avoid GERD in 3rd trimester by using PPI or H2 blocker
• For mild - moderate persistent asthma: salbutamol inhaler 1-2 puffs TDS or corticosteroid inhaler (i.e.

beclomethasone)

• For acute and/or severe exacerbations:
• Admit to HDU

Clinical description

• 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

 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: continue regular inhaler prn
• Use of IV hydrocortisone if patient has been on oral steroids >7.5mg/day for >2 weeks
• Misoprostol if indication for labour induction
• Oxytocin if PPH
• Avoid use of PGF and ergometrine

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