Undernutrition also occurs in utero. Babies born at full term but who are very small (under 2,500 grams or 5.5 pounds) have suffered from intrauterine growth restriction (IUGR).

The most significant cause of IUGR-related low birthweight is poor maternal nutrition. Other factors include woman’s small size, infections (including malaria and HIV/AIDS), smoking (and second-hand smoke), and indoor air pollution.

About 11 percent of infants born at full term in developing countries are born with low birthweight. The highest prevalence is in South Asia. The incidence of low birthweight seems to have remained roughly constant since around 2000.

Poor fetal growth contributes to birth asphyxia and infections, which account for 60 percent of neonatal deaths. Low birthweight babies are 20 times more likely to die in infancy than heavier babies. They are also more likely to suffer from chronic diseases as adults.

(Sources: Black et al. 2013, 2008; Conde-Agudelo 2002; EC-FAO Programme on Linking Information and Decision Making to Improve Food Security 2007; UNICEF 2007; Zhu, B P et al. 1999.)