Birth weight
Encyclopedia
Body weight
The term body weight is used in daily English speech as well as in the contexts of biological and medical sciences to describe the mass of an organism's body. Body weight is measured in kilograms throughout the world, although in some countries it is still measured in pounds or stones and pounds...
(more technically "mass
Mass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...
" - see mass versus weight
Mass versus weight
In everyday usage, the mass of an object is often referred to as its weight though these are in fact different concepts and quantities. In scientific contexts, mass refers loosely to the amount of "matter" in an object , whereas weight refers to the force experienced by an object due to gravity...
) of a baby
Infant
A newborn or baby is the very young offspring of a human or other mammal. A newborn is an infant who is within hours, days, or up to a few weeks from birth. In medical contexts, newborn or neonate refers to an infant in the first 28 days after birth...
at its birth
Childbirth
Childbirth is the culmination of a human pregnancy or gestation period with the birth of one or more newborn infants from a woman's uterus...
.
There have been numerous studies that have attempted, with varying degrees of success, to show links between birth weight and later-life conditions, including diabetes, obesity
Obesity
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...
, tobacco smoking
Tobacco smoking
Tobacco smoking is the practice where tobacco is burned and the resulting smoke is inhaled. The practice may have begun as early as 5000–3000 BCE. Tobacco was introduced to Eurasia in the late 16th century where it followed common trade routes...
and intelligence.
Determinants
There are basically two distinct determinants for birth weight:- The duration of gestation prior to birth, that is, the gestational ageGestational ageGestational age relates to the age of an embryo or fetus . There is some ambiguity in how it is defined:*In embryology, gestational age is the time elapsed since conception. This interval is also termed fertilisation age....
at which the child is born
- The prenatal growth rate, generally measured in relation to what weight is expected for any gestational age.
The incidence of birth weight being outside what is normal is influenced by the parents in numerous ways, including:
- GeneticsGeneticsGenetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
- The healthHealthHealth is the level of functional or metabolic efficiency of a living being. In humans, it is the general condition of a person's mind, body and spirit, usually meaning to be free from illness, injury or pain...
of the mother, particularly during the pregnancy - Environmental factors, including exposure of the mother to secondhand smoke
- Economic status of the parents gives inconsistent study findings according to a review on 2010, and remains speculative as a determinant.
- Other factors, like multiple births, where each baby is likely to be outside the AGA, one more so than the other
Abnormalities
- A low birth weightLow birth weightLow birth weight is defined as a birth weight of a liveborn infant of less than 2,500 g. regardless of gestational age-Causes:LBW is either the result of preterm birth or of the infant being small for gestational age , or a combination of...
can be caused either by a preterm birth (low gestational age at birth) or of the infant being small for gestational ageSmall for gestational ageSmall for gestational age babies are those who are smaller in size than normal for the baby's sex and gestational age, most commonly defined as a weight below the 10th percentile for the gestational age.-Terminology:...
(slow prenatal growth rate), or a combination of both. - A very large birth weight is usually caused by the infant having been large for gestational ageLarge for gestational ageLarge for gestational age is an indication of high prenatal growth rate, often defined as a weight that lies above the 90th percentile for that gestational age...
Influence on adult life
Studies have been conducted to investigate how a person's birth weight can influence aspects of their future life. This includes theorised links with obesityObesity
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...
, diabetes and intelligence.
Obesity
A baby born small or large for gestational age (either of the two extremes) is thought to have an increased risk of obesityObesity
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...
in later life.
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.
Diabetes
Babies that have a low birth weight are thought to have an increased risk of developing type 2 diabetes in later life.Intelligence
Some studies have shown a direct link between an increased birth weight and an increased intelligence quotientIntelligence quotient
An intelligence quotient, or IQ, is a score derived from one of several different standardized tests designed to assess intelligence. When modern IQ tests are constructed, the mean score within an age group is set to 100 and the standard deviation to 15...
.
Epidemiology
See also
- Barker's hypothesis
- MOMO syndromeMOMO syndromeMOMO syndrome is an extremely rare genetic disorder which belongs to the overgrowth syndromes and has been diagnosed in only six cases around the world, and occurs in 1 in 100 million births. The name is an acronym of the four primary aspects of the disorder: Macrosomia , Obesity, Macrocephaly and...
- Low birth weight paradoxLow birth weight paradoxThe low birth weight paradox is an apparently paradoxical observation relating to the birth weights and mortality of children born to tobacco smoking mothers. Low birth weight children born to smoking mothers have a lower infant mortality rate than the low birth weight children of non-smokers...
- Prenatal nutrition and birth weightPrenatal nutrition and birth weightNutrition and weight management before and during pregnancy has a profound effect on the development of infants. This is a rather critical time for healthy fetal development as infants rely heavily on maternal stores and nutrient for optimal growth and health outcome later in life. Prenatal...
External links
- "Intrauterine growth restriction (IUGR)" at Health System, University of VirginiaUniversity of VirginiaThe University of Virginia is a public research university located in Charlottesville, Virginia, United States, founded by Thomas Jefferson...
- "Researchers link low birth weight to lower achievement"
- "Management of Suspected Fetal Macrosomia"
- "Vit D linked to baby birth weight" at BBC NewsBBC NewsBBC News is the department of the British Broadcasting Corporation responsible for the gathering and broadcasting of news and current affairs. The department is the world's largest broadcast news organisation and generates about 120 hours of radio and television output each day, as well as online...
, 25 April 2006 - Born in Bradford - 2006 cohort study into the causes of low birth weight and infant mortality in Bradford, UK
- Intrauterine Growth Restriction Help - IUGR factors and solutions