Newborns can be small if the mother suffered nutritional deficiencies during pregnancy.
If a mother suffers hunger during pregnancy she carries serious risks both to herself and to the child. For example, pregnant women who are anaemic have a higher risk of pre-term delivery, and higher rates of miscarriage and foetal abnormalities. After birth there are further problems of nutrition during lactation. On the one hand, a mother's post-partum nutrition must remain high if the infant's survival chances are not to be compromised. Low birth-weight babies have low, quickly exhausted reserves of iron, which cannot be easily replaced through the breast milk of an anaemic mother.