Pregnancy airway changes

Weight gain (12-20 kg)	Enlarging gravid uterus Increasing total body water and interstitial fluid Increasing blood volume Deposition of new fat Enlargement of the breasts
Respiratory system	Decrease in respirator reserve volume Decrease in functional residual capacity (20%-30%) Increased oxygen consumption More rapid desaturation
Airway	Increased oral, nasal, pharyngeal, and tracheal mucosal edema Vascular engorgement of oral, pharyngeal, and nasal capillaries Edema of face and neck Advancement of Mallampati classification with pregnancy Advancement of Mallampati classification with bearing down during labor
Cardiovascular system	Inferior caval syndrome (supine hypotensive syndrome) requiring left uterine tilt
Gastrointestinal system	Steadily increasing intragastric pressure as pregnancy progresses Decreased lower esophageal sphincter tone due to increasing progesterone Symptomatic gastroesophageal reflux Distortion of gastric anatomy Increased gastric acidity