Mallampati class changes during pregnancy, labour, and after delivery: can these be predicted?

BACKGROUND: An increase in Mallampati class is associated with difficult laryngoscopy in obstetrics. The goal of our study was to determine the changes in Mallampati class before, during, and after labour, and to identify predictive factors of the changes.

METHODS: Mallampati class was evaluated at four time intervals in 87 pregnant patients: during the 8th month of pregnancy (T(1)), placement of epidural catheter (T(2)), 20 min after delivery (T(3)), and 48 h after delivery (T(4)). Factors such as gestational weight gain, duration of first and second stages of labour, and i.v. fluids administered during labour were evaluated for their predictive value. Mallampati classes 3 and 4 were compared for each time interval. Logistic regression was used to test the association between each factor and Mallampati class evolution.

RESULTS: Mallampati class did not change for 37% of patients. The proportion of patients falling into Mallampati classes 3 and 4 at the various times of assessment were: T(1), 10.3%; T(2), 36.8%; T(3), 51.7%; and T(4), 20.7%. The differences in percentages were all significant (P<0.01). None of the evaluated factors was predictive.

CONCLUSIONS: The incidence of Mallampati classes 3 and 4 increases during labour compared with the pre-labour period, and these changes are not fully reversed by 48 h after delivery. This work confirms the absolute necessity of examining the airway before anaesthetic management in obstetric patients.