When mothers actively smoke during pregnancy, their child is at a higher risk of being born with a low birth weight. Smoking can also be a stress management tool used by expecting mothers. There is some support for lower socioeconomic status of the parents being a determinant of low birth weight, but there is conflicting evidence, as socioeconomic status is tied to many other factors. Neonatal care
Most babies admitted to the NICU are born before 37 weeks of pregnancy or have low birth weight which is less than 5.5 pounds (2.5 kg). They could also have a medical condition that requires special care. In the United States nearly half a million babies are born preterm. Because of this, many of these babies also have low birth weights. There are four levels of care in the neonatal care units. Intensive Care, High Dependency Care, Low Dependency, and Transitional Care are the four levels:
Intensive Care: For babies with serious problems. This includes babies born three months early and have extremely low birth weight. High Dependency Care: For babies with less serious problem, but who still may not to be looked after or babies that are recovering from a critical illness. Low Dependency Care: For babies that do not need a continuous supervision. Transitional Care: For babies that still need medical treatment, but are well enough to be called for at their mothers bedside.
Middle aged adults with low birth weight present with a higher chance of obesity and diabetes. Children that are born under six pounds were 1.27 times more likely to develop diabetes compared to babies born at a healthy weight over six pounds. Growth hormone (GH) therapy at a certain dose induced catch-up of lean body mass (LBM). However percentage body fat decreased in the GH-treated subjects. Bone mineral density SDS measured by DEXA increased significantly in the GH-treated group compared to the untreated subjects, though there is much debate over whether or not SGA (small for gestational age) is significantly adverse to children to warrant inducing catch-up. Babies that have a low birth weight are thought to have an increased risk of developing type 2 diabetes in later life. Low birth weight is linked with increase rates of obesity, insulin resistance, and type 2 diabetes and it is shown that children with the low birth weights have increased leptin levels after they catch up growth during childhood. Adiponectin levels are positively related with birth weight and BMI in babies with an increase of risk of type 2 diabetes. The leptin and adiponection mechanisms are still being studied when involving low birth weight. Around the world
There is much variation regarding birth weight within continents, countries, and cities. Even though over 20 million babies are born each year with low birth weight, it is hard to know the exact number as more than half of babies born in the world are not weighed at birth.