Airway management remains a cornerstone of safe anaesthetic practice and is particularly critical in obstetric patients, who are at increased risk for airway-related complications due to pregnancy induced anatomical and physiological changes. While much attention has been devoted to the management of the unexpected difficult airway in paediatric and adult populations【1】【2】, the unique challenges presented by pregnancy have important implications for clinical outcomes.

Adverse respiratory events and failed airway management are significant contributors to perioperative morbidity and mortality across all age groups, including obstetric patients【3】【4】. In the context of pregnancy, factors such as airway oedema, increased body mass index, gestational weight gain, and rapid fluid shifts may lead to a rapid progression from a seemingly normal airway to one that is difficult or impossible to secure【5】. Traditional airway assessment tools, such as the Mallampati classification, remain essential but must be interpreted with caution given the dynamic changes that can occur during labour and the postpartum period.

Early identification and preparation for the potentially difficult airway are central to improving patient safety in the obstetric setting. Advances in airway management techniques and updated clinical guidelines continue to evolve in response to ongoing challenges, emphasizing the need for systematic assessment and proactive strategies【6】. However, there is limited prospective data evaluating the serial changes in airway anatomy among pregnant women in the Indian population, particularly in relation to modifiable clinical risk factors.

The present study aims to address this gap by evaluating the progression of Mallampati class during late pregnancy, labour, and the early postpartum period in Indian women, with the goal of identifying predictors of difficult airway and informing strategies for risk reduction in obstetric anaesthesia.

OBJECTIVE

The objectives of this study were:

To assess serial changes in Mallampati classification among Indian women during late pregnancy, labour, and the early postpartum period.

To determine the incidence and timing of progression to higher Mallampati classes, indicating increased risk of difficult airway.

To identify clinical and peripartum predictors—such as body mass index, gestational weight gain, intravenous fluid administration, and comorbidities—associated with increased Mallampati class.

To provide evidence-based recommendations for airway assessment and risk stratification in obstetric anaesthesia practice.

Study Design and Setting

This was a prospective observational study conducted over a two-year period at the Department of Anaesthesiology & Critical Care, SCB Medical College & Hospital, Cuttack, Odisha a tertiary care centre in India. The study was approved by the institutional ethics committee, and written informed consent was obtained from all participants.

Study Population

Ninety pregnant Indian women aged over 21 years were enrolled. Inclusion criteria were singleton pregnancy and willingness to participate. Exclusion criteria included age below 21 years, prior anaesthetic exposure in the current pregnancy, eclampsia, and refusal to consent.

Data Collection

Demographic details (age, body mass index *BMI+, gravida status, gestational weight gain, and comorbidities such as hypertension, gestational diabetes, hypothyroidism, and anaemia) were recorded at recruitment. Clinical details regarding labour were collected, including duration of the first and second stages and the volume of intravenous fluids administered during each stage.

Airway Assessment

Mallampati classification was evaluated for each participant at four predefined time points: 32–34 weeks gestation (baseline) On admission for labour (peripartum)

2–4 hours post-delivery 48–72 hours post-delivery

Mallampati grading was performed by trained anaesthesiologists using a standardized protocol with the patient in a sitting position, mouth fully open, and tongue protruded without phonation.

Statistical Analysis

All data were compiled and analyzed using SPSS software version 20. Descriptive statistics included mean, standard deviation, frequencies, and percentages. The Wilcoxon signed-rank test was used to assess changes in Mallampati classification across serial time points. Pearson’s correlation coefficients were calculated to evaluate associations between clinical variables (BMI, weight gain, intravenous fluid volume, labour duration, comorbidities) and maximum Mallampati class reached. Statistical significance was defined as a p-value < 0.05.

Patient Demographics and Baseline Characteristics

A total of 90 pregnant women were enrolled in the study. The majority of participants were aged 30 years or younger (n = 79, 87.8%), while 11 women (12.2%) were over 30 years of age. The mean body mass index (BMI) was 28.42, with most women classified as overweight or obese: 8 (8.9%) had a BMI of 18.5–24.99, 52 (57.8%) had a BMI of 25–29.99, 29 (32.2%) had a BMI of 30–34.99, and 1 (1.1%) had a BMI of 35–39.99.

Gestational weight gain of less than 15 kg was observed in 60 women (66.7%), while 30 (33.3%) gained more than 15 kg during pregnancy. More than half of the participants (n = 56, 62.2%) were primigravida, and the remainder (n = 34, 37.8%) were multigravida.

Comorbid conditions were present in 43 women (47.8%). The most common comorbidities included pregnancy-induced hypertension (PIH) in 16 women (17.8%), hypothyroidism in 12 (13.3%), gestational diabetes in 8 (8.9%), and anaemia in 7 (7.8%).

Table 1. Patient Demographics and Baseline Characteristics

Labour and Peripartum Clinical Data

Most participants experienced a first stage of labour lasting between 15 and 20 hours (n = 70, 77.8%), while 16 women (17.8%) had a prolonged first stage (>20 hours) and only 4 (4.4%) had a duration less than 15 hours. The duration of the second stage of labour was less than one hour in 46 women (51.1%) and exceeded one hour in 44 women (48.9%).

Regarding intravenous fluid administration, 79 women (87.8%) received between 500 and 1000 ml during the first stage of labour, while 11 (12.2%) received more than 1000 ml. During the second stage of labour, 45 women (50%) received between 50 and 100 ml, and 44 (48.9%) received more than 100 ml of intravenous fluids.

Table 2. Labour and Peripartum Clinical Parameters

This profile reflects a predominance of protracted labour and moderate to high volumes of intravenous fluid administration during the peripartum period.

Serial Mallampati Classification Changes

Serial assessment of the Mallampati classification revealed significant dynamic changes in airway anatomy throughout the peripartum period. At baseline (32–34 weeks gestation), the majority of women were classified as Mallampati class I (n = 56, 62.2%) or II (n = 20, 22.2%), with only a small proportion in classes III (n = 13, 14.4%) and IV (n = 1, 1.1%).

A marked shift toward higher Mallampati classes was observed as pregnancy progressed to labour and the postpartum period. At the time of admission for safe confinement, the proportion of women with Mallampati class I decreased to 32.2%, while those in classes II, III, and IV rose to 48.9%, 25.6%, and 1.1%, respectively. The change was most pronounced 2–4 hours post-delivery, with only 3.3% remaining in class I and a sharp increase in classes III (45.6%) and IV (23.3%).

At 48–72 hours postpartum, the trend persisted, with 68.9% of women remaining in Mallampati class IV, and only 2.2% in class I. Overall, 64% of women demonstrated a transition from Mallampati I/II to III/IV during the peripartum period.

Statistical analysis using the Wilcoxon signed-rank test showed that increases in Mallampati class across all assessed time points were highly significant (p < 0.001 for all major transitions).

Table 3. Mallampati Class Distribution at Each Time Point (n = 90)

Figure 1. Serial Mallampati class distribution at four time points

Correlates and Predictors of Mallampati Class Change

Analysis of clinical predictors revealed significant associations between increased Mallampati class during the peripartum period and several patient and labour-related factors.

Body mass index (BMI) was strongly correlated with higher Mallampati class at all time points (Pearson’s r = 0.40–0.65, p < 0.001). Women with BMI ≥25 kg/m² were significantly more likely to transition to Mallampati class III or IV during and after labour. Gestational weight gain was also a significant predictor (r = 0.53–0.62, p < 0.001), with women gaining more than 15 kg exhibiting greater increases in Mallampati score.

The volume of intravenous fluids administered during the first stage of labour was significantly correlated with higher Mallampati class (r = 0.26–0.34, p = 0.001–0.016), while a weaker but still notable correlation was observed for the second stage (r = 0.19–0.27, p = 0.008–0.070). The presence of comorbidities such as pregnancy-induced hypertension, gestational diabetes, and hypothyroidism was also associated with higher Mallampati classes (all p = 0.001).

In contrast, age and parity (primigravida vs multigravida) did not show significant associations with Mallampati class changes (all p > 0.3). Duration of the first stage of labour showed a minimal but statistically significant association with higher Mallampati class, whereas the second stage had only a weak effect (significant for Mallampati II, r = 0.22, p = 0.036).

Table 4. Correlation Analysis for Predictors of Increased Mallampati Class

Figure 2. Scatter plot illustrating the relationship between BMI and maximum Mallampati class reached.

Clinical Implications of Mallampati Class Change

A significant proportion of women in this cohort developed features suggestive of a potentially difficult airway during labour and in the immediate postpartum period. At baseline, only 14.4% of women were classified as Mallampati class III and 1.1% as class IV. However, these proportions rose sharply following delivery: by 2–4 hours post-delivery, 45.6% of women were in class III and 23.3% in class IV. At 48–72 hours postpartum, the number of women with Mallampati class IV remained high (68.9%).

Overall, 64% of the study participants experienced a progression from Mallampati class I/II to class III/IV at some point during labour or the postpartum period, indicating a marked increase in the risk of difficult airway. Notably, in the subgroup of women with BMI ≥30 kg/m² or gestational weight gain >15 kg, nearly all developed Mallampati class III or IV during or after labour.

These changes were most pronounced immediately after delivery but persisted for at least 72 hours in the majority of cases. No significant differences in this pattern were observed between primigravida and multigravida women.

Figure 3. Line chart showing the percentage of patients with Mallampati class III/IV across the four time points (baseline, admission, 2–4 hours post-delivery, 48–72 hours postpartum).  

The present study highlights significant and dynamic changes in airway anatomy, as reflected by the Mallampati classification, during late pregnancy, labour, and the postpartum period in Indian women. The progression to higher Mallampati classes observed in this cohort has substantial implications for obstetric airway management.

Difficult airway is a major concern in obstetric anaesthesia and remains a leading cause of anaesthesia-related morbidity and mortality. Samsoon and Young’s classic study reported a 1 in 30 incidence of difficult tracheal intubation in obstetric patients, considerably higher than in the nonpregnant surgical population【7】. In our cohort, 64% of women transitioned from Mallampati class I/II to class III/IV at some point during the peripartum period, suggesting a striking rise in the proportion at risk for difficult intubation. This observed trend is higher than historical rates but mirrors findings from more recent analyses.

Meta-analyses, such as that by Shiga et al., confirm that the Mallampati classification remains a robust bedside test for predicting difficult intubation, with higher classes correlating with increased intubation difficulty (odds ratio up to 7.2 for class IV) 【8】. Our results align with these benchmarks, with nearly all women reaching class III/IV in the highest BMI subgroup, emphasizing the importance of airway reassessment during labour.

Standard references such as Miller’s and Benumof’s textbooks underline those physiological changes in pregnancy, including mucosal oedema, increased blood volume, and weight gain, all contribute to a higher risk of difficult airway【9】【10】. Our finding that BMI ≥25 kg/m² and gestational weight gain >15 kg were significant predictors of higher Mallampati class is directly consistent with these established risk factors. Furthermore, our data show that intravenous fluid administration during labour—frequently necessary for obstetric management—was associated with a greater increase in Mallampati score, supporting the theoretical and empirical evidence that fluid shifts exacerbate airway oedema【11】【12】.

Guidelines and expert panels, such as those from Crosby et al., emphasize the need for repeated airway evaluation in obstetric patients, particularly as labour progresses or clinical circumstances change【13】. Our findings strongly support this recommendation; only 16% of women had a potentially difficult airway at baseline, but this rose to nearly 70% post-delivery, and to 97% at 48–72 hours postpartum. This dynamic risk underscores the limitations of relying solely on a single prelabour airway assessment.

Despite advances in training and equipment, failed or difficult intubation in obstetric anaesthesia continues to be a significant cause of maternal morbidity. Rahman and Jenkins highlighted that although the frequency of failed intubation in obstetrics is not increasing, adverse outcomes persist due to suboptimal management and lack of preparedness【14】. Our results suggest that the transient but profound increase in Mallampati class during and after labour should alert clinicians to the need for vigilance, preparation, and possibly the use of advanced airway adjuncts in high-risk women.

Kodali et al. prospectively demonstrated that Mallampati scores can increase by as much as two classes during labour and may not normalize immediately postpartum, which is consistent with our finding that elevated scores persist for at least 72 hours after delivery【15】. This supports the rationale for continued airway risk stratification in the early postpartum period, especially when repeat anaesthesia may be required.

Ezri et al. further reported that both weight gain and BMI independently predict worsening airway view during pregnancy and postpartum, matching our statistical findings of significant correlations between BMI, weight gain, and maximum Mallampati class reached【16】. The lack of significant association with maternal age or parity in our study is also consistent with previous large-scale analyses.

Finally, studies such as those by Izci et al. confirm that the upper airway is particularly susceptible to physiological changes during pregnancy and in conditions such as pre-eclampsia, reinforcing the need for tailored perioperative assessment strategies in this population【17】.

In summary, our results confirm and extend the published evidence that the obstetric airway is not static, and the risk of difficult intubation can increase dramatically within a short timeframe around delivery. The integration of serial Mallampati assessment, attention to modifiable risk factors (such as fluid management), and a high index of suspicion in obese or high weight-gain patients are essential strategies for improving maternal safety.

Dynamic changes in airway anatomy, as reflected by the Mallampati classification, are common during labour and the early postpartum period in Indian women. The risk of difficult airway increases significantly, particularly in those with higher BMI, excessive gestational weight gain, and greater intrapartum fluid administration. Serial airway assessment should be incorporated into obstetric practice, and heightened vigilance is warranted for women with multiple risk factors. Early recognition and proactive management of airway changes may help reduce the risk of anaesthesiarelated complications in the obstetric population.

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