Study examines relationship between growth restriction and risk of childhood mortality

Almost all children live to see their eighteenth birthday despite a severe growth restriction, as long as they have survived their first month during infancy. This is indicated in a study by researchers at Karolinska Institutet, which is published in the journal PLOS Medicine.

Reducing child mortality is one of the UN's Millennium Development Goals, but the work is progressing slowly. Improved maternal health and a desire to reduce growth restriction during the fetal period could be two ways decreasing child mortality. Growth restriction in fetuses has previously been associated with an increased risk of stillbirth and increased mortality in the neonatal period, but whether or not growth restriction also has an affect on long-term survival in children is unclear.

In the study in question, the researchers analyzed the relationship between severe or moderate growth restriction and the risk of death later in childhood in a total of 3.8 million live-born children and 2.8 million siblings born in Sweden between 1973 and 2012.

Increased risk of death among children with growth restriction

The researchers examined the mortality in the range of one month up to eighteen years of age by comparing children who had suffered from growth restriction with children experiencing normal growth. Siblings were also compared, where one of them had been subject to growth restriction. Sibling comparisons make it possible to take into account a variety of environmental factors, such as socioeconomic factors and lifestyle as well as genetic factors from the mother, which may be important with regard to child mortality.

Approximately 1 out of 105 children with severe growth restriction died before reaching their eighteenth birthday, compared to 1 out of 202 with moderate growth restriction and 1 out of 289 children with normal development.

"This corresponds to 2.6 times or a 160 per cent increase in the risk of death among children with severe growth restriction, both when compared with all children experiencing normal growth and compared with siblings who had normal fetal growth. Moderate growth restriction during the fetal period was also a risk factor for death before reaching eighteen years of age, with these children having a 37 per cent increased risk," says Jonas F. Ludvigsson, professor at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, and the study's lead author.

The highest risk of death was observed during the first year for children suffering from growth restriction, where infections and neurological disorders were the most common causes of death.

"Growth restriction during pregnancy is not only dangerous for the newborn's health but has also been associated with an increased risk of death later in childhood. But as a parent, you should still remember that even among children who have experienced severe growth restriction and made it past the first month, 99 out of 100 will get to celebrate their eighteenth birthday regardless," says Jonas Ludvigsson.