What Is the Normal Birth Weight Range?

Updated July 19, 2017

After time of birth, the next and more important statistic attached to a newborn's name is his birth weight. It is far more important than just giving a new father bragging rights. It will help determine her overall prognosis for survival, what immediate supportive care she may need, his expected length of stay in the hospital, and is an indication of possible future complications.


According to Texas Department of State Health Services guidelines, normal birth weight range is 2.27kg., 170gr. to 3.63kg. 369gr., although the average newborn weighs in at 3.18kg., 170gr. Low birth weight is below 2.27kg., 6 oz., very low birth weight is below 1.36kg., 4 oz., and extremely low birth weight is below 0.998kg. On the other end of the scale, high birth weight is between 3.63kg., 14 oz. and 4.08kg., 3 oz. Babies weighing over 4.08kg., 3 oz. are classified as large for gestational age.


Although birth weight is not a predictor of adult size, low birth weight can be linked to factors that may affect normal growth and development of children. These risk factors include vision and hearing loss, diminished cognitive ability, movement disorders including cerebral palsy, school achievement struggles and future health issues, which, according to the International Epidemiological Association, may include high blood pressure, asthma, heart disease, diabetes and some cancers. Large for gestational age infants may exhibit difficulty maintaining blood sugars and are often closely monitored the first few days of life.

Contributing Factors

Ethnic background and size of both parents as well as the size of previous infants born to the mother, can affect birth weight. A placenta that is not well attached, such as over a site of old scarring, or partially attached across the cervix will deliver less blood and nutrition to a foetus, thereby affecting birth weight. Overall health issues of the mother, including poorly controlled diabetes or blood pressure or chronic disease contribute, especially when they result in early delivery. Babies born to young teenage mothers are at higher risk for low birth weight. Multiple babies within the womb are also at much greater risk for both premature delivery and low birth weight.


Pregnant women can optimise their chances of having a normal birth weight infant by eating a healthy diet, getting plenty of rest and avoiding the known risk factors like tobacco, alcohol and any drugs not approved by an obstetric health care provider. Additionally, regular checkups will increase chances of early intervention for any health problems which might put an infant at risk for low birth weight or early delivery.


Not all small babies will be labelled low birth weight. For example, a 2.27kg., 2 oz. baby born at full term to parents of Guatamalan descent may be average size for those parents and that culture.

Newborns will normally lose 6 to 10 per cent of their birth weight, which is typically 5 to 11 oz. for an average infant. If a baby does not regain his weight in approximately two weeks, his health care provider should be notified.

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About the Author

Kathy Boll Hughes began writing pamphlets for Newborn ICU parents in 1971 and continues to write educational medical articles. Her published work is currently found on and She is also a ghost writer for a just-released medical text. Hughes holds a Bachelor of Science in Nursing from San Diego State.