box ► Recent estimates of low birth weight (LBW) (weight <2500 g) indicate the burden to be high; 20.5 million babies are born too small annually, although data from low-income countries is sparse. ► The WHO's antenatal care guidelines recommend supplementation with 'balanced energy and protein' (BEP) during pregnancy in undernourished settings (where >20% women are too thin based on their body mass index). ► Motivated by equity, we make the case for targeting individual, higher-risk women for BEP supplementation, which would be safe, affordable and likely more impactful by giving all vulnerable women access to this effective intervention. ► Innovative, programmatic action using such a precision public health approach is needed to improve women's health and accelerate progress towards the 2030 target for reducing LBW by 30%.