Exclusive breastfeeding is recommended for the first six months of life and complementary feeding of nutritious food alongside breastfeeding for children aged six months to 2-years-old. Prolonged exclusive breastfeeding is associated with undernutrition because breast milk alone is nutritionally insufficient for children over six months old. Breastfeeding in long time with inadequate complementary feeding leads to growth failure due to insufficient nutrients which are essential for childhood development. The relationship between undernutrition and prolonged duration of breastfeeding is mostly observed among children from poor households and whose parents are uneducated as they are more likely to continue breast-feeding without meeting minimum dietary diversity requirement. Maternal nutrition Poor maternal nutrition during pregnancy and breastfeeding can lead to stunted growth of their children. Proper nutrition for mothers during the prenatal and postnatal period is important for ensuring healthy birth weight and for healthy childhood growth. Prenatal causes of child stunting are associated with maternal undernutrition. Low maternal BMI predisposes the fetus to poor growth leading to intrauterine growth retardation, which is strongly associated with low birth weight and size. Women who are underweight or anemic during pregnancy, are more likely to have stunted children which perpetuates the inter-generational transmission of stunting. Children born with low birthweight are more at risk of stunting. However, the effect of prenatal undernutrition can be addressed during the postnatal period through proper child feeding practices. Maternal undernutrition increases the risk of stunting at 2 years age. Based on data from 19 birth cohorts from LMICs, 20% of stunting is attributed to being born small-for-gestational-age (SGA). Further, estimated stunting at 2 years attributed to fetal growth restriction and preterm birth in 2011 was 33% in all developing countries and 41% in South Asia. Restricted pre- and postnatal growth are in turn important determinants of short adult height, increasing the likelihood of the next generation also being stunted. Sanitation There is most likely a link between children's linear growth and household sanitation practices. The ingestion of high quantities of fecal bacteria by young children through putting soiled fingers or household items in the mouth leads to intestinal infections. This affect children's nutritional status by diminishing appetite, reducing nutrient absorption, and increasing nutrient losses.The diseases recurrent diarrhea and intestinal worm infections (helminthiasis) which are both linked to poor sanitation have been shown to contribute to child stunting. Research on a global level has found that the proportion of stunting that