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BACKGROUND REPORT MARCH 19, 2009
Prematurity and Low Birth Weight
Low birth weight
is defined by the World Health Organization as a child who is born weighing
less than 5.5 pounds. The condition can be the result of a premature
birth or restricted growth of the infant due to the mother's health
and nutrition.
Mothers living in deprived socioeconomic conditions frequently have
low birth weight infants.
While some low birth weight babies may be perfectly healthy, low birth
weight due to restricted growth can negatively affect a child's growth
and susceptibility to disease throughout life. Premature birth and low
birth weight are both major causes of neonatal death.
About 20 million
infants, or about 23.8 percent of all births, are born each year at
a low birth weight. Infants with low birthweight are 20 times more likely
to die than heavier babies.
More than 95 percent of low birth weight babies are born in developing
countries, however data collection for low birth weight is difficult
because babies are not weighed at birth in many countries.
Nearly 4 million
babies die in the first month of life and low birth weight and premature
birth are major causes.
Half of all
low birth weight babies are born in South-central Asia, where 27 percent
of infants are born below 5.5 pounds. Low birth weight levels in sub-Saharan
Africa are
around 15 percent and the Caribbean has a level of 14 percent. North
America averages 8 percent while Europe has the lowest prevalence at
6 percent.
Premature babies
are born before 37 weeks of pregnancy, known as preterm labor.
Babies that
are low weight from restrictions on fetal growth are sometimes a reflection
of health of the mother. Alcohol, illicit drugs and smoking can all
limit fetal growth. Pregnant women who smoke are nearly twice as likely
to have low birth weight babies and are at increased risk of premature
delivery.
Poor maternal
health and nutrition are the most common causes of low birth weight
in the developing world. Mothers with poor nutritional status before
conception, a comparatively short stature and poor nutrition during
pregnancy are all factors in low birth weight.
Teenage mothers
whose bodies are not fully grown are especially susceptible to giving
birth to babies with low birth weight.
Low birth weight
babies are less than 5.5 pounds at birth and at increased risk of death.
They are more likely to have health problems during the newborn period,
and may have difficulty feeding and gaining weight, maintaining body
temperature and may have low oxygen levels at birth. Low birth weight
babies are more susceptible to disease, including, a breathing problem
common in premature babies, bleeding in the brain, and heart and intestinal
problems.
A mother's
prenatal care is a key factor in preventing preterm births and low birth
weight infants. Proper nutrition and weight gain, as well as avoiding
alcohol and cigarettes can prevent low birth weight.
Preventing
low birth weight may also include micronutrient supplementation and
preventing and treating diseases such as malaria and HIV/AIDS in pregnant
women.
Low birth weight babies need care in a neonatal intensive care unit,
and usually need a temperature-controlled bed and special food, potentially
through a tube into the stomach. These interventions are costly and
can be difficult if not impossible to obtain in developing countries.
A process called kangaroo mother care, where the mother straps the baby
to her, providing continuous skin-to-skin contact, has been shown to
provide some of the warmth, stimulation and protection from infection
that a newborn needs to survive.
Sources: World
Health Organization, March of Dimes, UNICEF, University of Virginia,
Global Health Council |
