The terms low birthweight (LBW) and very low birth weight (VLBW) are still cited in public health reports, usually defined as <2.5 kg and <1.5 kg respectively.
These terms are not useful and can cause confusion as they combine smallness due to growth restriction and smallness due to prematurity.
Small for gestational age (SGA) or the older term ‘small for dates’ (SFD) is gestation specific and below the agreed normal limit at that gestational age. It can be applied to standardised fundal height (SFH) measurement, estimated fetal weight (EFW) or birthweight (BW).