Use of SAM and MAM Terminology in Infants Under 6 Months
No, the terms "severe acute malnutrition (SAM)" and "moderate acute malnutrition (MAM)" are not traditionally used for infants younger than 6 months according to WHO standards, though this is changing with recent WHO guidelines that now include this age group for the first time.
Current WHO Position
The WHO has historically excluded infants under 6 months from standard acute malnutrition classifications because:
- The 2006 WHO growth standards exclude infants shorter than 45 cm, making weight-for-length z-scores (WLZ) unreliable for the youngest infants 1
- Traditional diagnostic criteria (WLZ, MUAC thresholds) were developed and validated primarily for children aged 6-59 months 2
However, new WHO guidelines for management of SAM now include infants under 6 months for the first time 3. This represents a significant policy shift recognizing that approximately 4.7 million infants under 6 months are moderately wasted and 3.8 million are severely wasted globally 3.
Key Diagnostic Challenges for Infants <6 Months
Why This Age Group Is Different:
- Physiological and pathological differences demand different approaches from older children 3
- Standard anthropometric cutoffs require validation in this population
- MUAC shows promise as a diagnostic criterion and predicts mortality better than WLZ in this age group 1
- A MUAC threshold of <11.0 cm performed better than WLZ <-3 for predicting both inpatient and postdischarge mortality 1
Critical Caveat:
Case definitions for infants under 6 months remain inadequate and require urgent development 3. The evidence base is sparse, and criteria based on MUAC are promising but need further research before widespread implementation.
Management Approach When Terms Are Applied
When SAM/MAM terminology is used for infants <6 months (per new WHO guidelines):
- Focus on exclusive breastfeeding wherever possible as the core intervention 3
- Treat the mother-infant dyad, not just the infant 3
- Community-based breastfeeding support is essential but not the sole treatment 3
- Use the same therapeutic feeding approaches as for older children with SAM, though metabolic and nutrient needs may differ 4
Practical Recommendations
For nutrition surveys and clinical screening:
- Routinely include infants under 6 months to better define the burden and outcomes of acute malnutrition in this age group 3
- Consider MUAC <11.0 cm as a high-risk threshold requiring intervention 1
- Weight-for-age z-score (WAZ) also predicts mortality well in this population 1
Common Pitfall: Clinicians and nutritionists have traditionally overlooked this age group 3. With new WHO guidance, this population must now be actively identified and managed, despite the imperfect diagnostic criteria currently available.
The terminology is increasingly being applied to infants <6 months, but recognize that the evidence base remains limited and diagnostic thresholds are still being refined through ongoing research 3.