The airway becomes more difficult to manage, for numerous reasons.

Bag-mask ventilation becomes more difficult:

• The nasal mucosa is engorged, which means there is greater resistance to flow
• The upper airway mucosa is oedematous
• There has been weight gain

Laryngoscopy becomes more difficult:

• Upper airway oedema
• Breast enlargement
• The Mallampatti grade changes during pregnancy, largely because of oedema of the pharynx, and due to weight gain. It gets even worse with labour.

Less time is available for intubation:

• Decreased FRC, less time to intubate
• Increased oxygen consumption, less time to intubate

Intubation is more risky

• Increased risk of aspiration, decreased stomach emptying