Airway problems and changing Mallampati score during pregnancy and labor: a systematic review

During pregnancy, labor, and postpartum, physiological changes such as weight gain, hormonal fluctuations, or fluid retention may cause airway edema and soft tissue swelling. These factors impact Mallampati Classification, a predictive tool to investigate airway. A higher Mallampati class indicates a high-risk obstetric population. This systematic review explores the airway and Mallampati modification during the different pregnancy periods. Understanding the airway changes in pregnancy is critical to safely intubate, avoid adverse outcomes in maternal care and support clinical practice.

Research started using five databases, from the beginning to January 2025: Medline, Embase, Scopus, Cochrane Central Register of Controlled Trials, and ClinicalTrial.gov, with the following search terms: "Mallampati", "Mallampati grading", "Airway", "Airway changes", "Airway Obstruction", "pregnancy", "Delivery, Obstetric", "Anesthesia, Obstetrical". Articles included only studies covering a change in the Mallampati classification in pregnancy, labor, or postpartum. All the studies that did not concern airway changes in pregnancy or did not include a Mallampati classification were excluded. The quality of the included studies was assessed using a modified Newcastle-Ottawa Scale.

Ten articles met the inclusion criteria. Significant changes in Mallampati class during pregnancy, labor, and post-partum were evidenced. Grades III and IV of Mallampati Classification increased during pregnancy, reaching 51.7% at delivery, compared to 10.3% pre-pregnancy. Increased proportions of MMC III/IV were observed among women with hypertensive and preeclampsia conditions when compared with the normotensive population. During the postpartum, the Mallampati class partially receded toward pre-pregnancy levels, with approximately 82% returning to baseline within 36 to 48 h.

These findings evidenced the pregnancy-related airway changes and their dynamic process, highlighting the need for close vigilance, especially during labor in high-risk populations.

PROSPERO CRD42025635304.