Establishing a practical anthropometric measurement, with an appropriate cut-off threshold, to identify pregnant women as undernourished in humanitarian settings can assist in the implementation of necessary interventions to avoid unfavourable maternal and birth outcomes. A key gap in maternal nutrition is that there is currently no agreed-upon standard set in the Sphere Handbook that defines maternal acute undernutrition through an optimal, context-specific MUAC cut-off point (Sphere Association, 2018).

In 2013, Médecins Sans Frontières Switzerland undertook an extensive literature review (Ververs et al, 2013) of articles published between January 1995 and September 2012 exploring anthropometric indicators that are able to identify pregnant women as acutely undernourished and at risk for adverse outcomes – including maternal mortality, low birth weight (LBW), intra-uterine growth restriction (IUGR), pre-term birth (PTB), small-for-gestational-age (SGA), and stunting at birth.

The review concluded that maternal MUAC can be used as a reliable indicator of risk of LBW. Maternal MUAC was identified as the preferential indicator, as opposed to body mass index, maternal weight for gestational age, maternal weight gain, or maternal stature. Maternal MUAC has a strong association with birth weight, is a simple measurement to take, particularly in humanitarian contexts, and is independent from gestational age. The proposed conservative cut-off value to enrol pregnant women in nutritional programmes, most frequently supplementary feeding programmes, was a MUAC of <23 cm.

This scoping review aims to analyse studies published after September 2012, specifically focusing on determining the specific MUAC cut-off threshold used to identify adverse birth and maternal outcomes to understand if a MUAC of <23cm should be used rather than a MUAC of <21cm as is used in some humanitarian nutrition programmes.