Reduce the rate of low birthweight by at least one third

Overview

Normal birthweight is critical to future health and development

Birthweight is a strong indicator not only of a birth mother's health and nutritional status but also a newborn's chances for survival, growth, long-term health and psychosocial development.

A low birthweight (less than 2,500 grams) raises grave health risks for children. Low birthweight is a public health problem in most developing countries, in which an estimated 16 per cent of births result in low-birthweight babies. Babies who are undernourished in the womb face a greatly increased risk of dying during their early months and years. Those who survive have impaired immune function and increased risk of disease; they are likely to remain undernourished, with reduced muscle strength, throughout their lives, and to suffer a higher incidence of diabetes and heart disease. Children born underweight also tend to have cognitive disabilities and a lower IQ, affecting their performance in school and their job opportunities as adults.

Low birthweight can arise as a result of a baby being born too soon (at less than 37 weeks, also known as preterm birth) and/or being born too small for gestational age (small as a result of intrauterine growth restriction). Babies that are born prematurely and are also small for their gestational age have the worst prognosis.

In the developing world, low birthweight stems primarily from poor maternal health and nutrition. Three factors have most impact: poor maternal nutritional status before conception, short stature (due mostly to undernutrition and infections during childhood), and poor nutrition during pregnancy.

Inadequate antenatal weight gain in particular is a main cause of foetal growth retardation. Teenagers who give birth when their own bodies have yet to finish growing also have a greater risk of bearing underweight babies. Moreover, maternal diseases that are common in many developing countries, such as malaria, can significantly impair foetal growth. In addition, a heavy physical workload during pregnancy may also negatively impact birthweight.

Key interventions to prevent low birthweight, therefore, include improved food intake, micronutrient supplementation, preventing and treating diseases such as malaria and HIV/AIDS, educating girls and expectant mothers, and preventing teenage pregnancies.

Problems estimating low birthweight incidence

Almost 60 per cent of newborns in developing countries are not weighed; in South Asia, which has the highest incidence of low-birthweight babies, that figure is over 70 per cent. Those newborns who are weighed, meanwhile, are generally better off (more likely to be born in health facilities, urban areas and of better-educated mothers), which can lead to an under-estimation of the incidence of low birthweight.

UNICEF and the World Health Organization (WHO) have adjusted the under-reporting and misreporting of birthweights with results from household surveys (Multiple Indicator Cluster Surveys and Demographic and Health Surveys).

While improving unadjusted statistics, these rates may still underestimate the magnitude of the problem. It is critical, therefore, that all babies be properly weighed at birth.

References

United Nations Children's Fund/World Health Organization, Low Birthweight - Country, Regional and Global Estimates, UNICEF, New York, 2004.
 

MacDorman MF, Atkinson JO, 'Infant mortality statistics from the 1997 period linked birth/infant death data set', National Vital Statistics Report, vol 47 no. 23, 1999, pp. 1-23.

Barker, DJ (ed.), Fetal and infant origins of disease, BMJ Books, London, 1992.

A. Blanc and T. Wardlaw, Monitoring low birthweight: an evaluation of international estimates and updated estimation procedure, Bulletin of the World Health Organization, vol 83 no. 3,  2005, pp. 178 - 185.