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Average Weight and Length of a Newborn BabyLength and weight of a newborn baby indicates the health of a baby. Pediatricians maintain a chart of length, weight and head size of the baby. The growing graph means the baby is healthy and poor growth chart means any health problem.

During first year, a healthy baby should grow triple the birth weight and length, 50% more than that of birth time. Duration of pregnancy affects the weight of the baby. Weight and length of a premature baby is much less than a normal baby. The pre mature baby is needed to keep in NICU for few days. These are the factors which affect the average birth weight:

  • Premature birth
  • Gender of the baby
  • In case of twins, triplet or multiple births, Babies have much less weight
  • Genetic factor- Size of the parents affects the weight and size of the baby
  • Baby’s health
  • Race, ethnicity, nutrition during pregnancy etc
  • Any abnormality of uterus

Average birth weight of newborn baby varies in different countries according to the above mentioned factors. In a developed country where pregnant lady doesn’t have to face dearth of nutrition, average weight info is as follows:

A single baby born after full time of pregnancy (40 weeks) weighs 3500 gms.  (7 lbs. 11 ounces) . 5% babies born with less than 2500 gms and 0.08% are born with extremely low weight 1500 gms. Such babies are needed to be kept in NICU.

Average body length of newborn– 14’’-20’’ (35.6cms – 50.8cms). There is a little difference in length and weight of boy baby and girl baby. Average length of male baby is 50.6 cms. and that of female baby is 50.1cms. 4% babies are born below 46 cms of length.

Average boys weigh 100 gms. more than girls. Overall average birth weight has increased marginally. It was 3372 gms. in 1989-91 whereas it was 3434 gms in 2004-06.
The data above are according to developed countries.

Weight of twins at birth time

Generally the pregnancy period in case of twins is 37 weeks, and in case of triplet it is 34 weeks. More than 50% of multiple births are premature, therefore having low weight. Whereas only 6.2% of singleton babies are born underweight. Average birth weight of twins are 5 pounds, 5 ounces . Twins may be of different weight. It’s not necessary that both the twins having same weight.

Weight and health are related

Infant mortality within first year is caused mainly due to low birth weight. But advanced new born medical care has reduced the death rate. Small percent of such babies develop mental retardation, learning problem, cerebral palsy, vision and hearing problem.

Always a baby with low weight doesn’t mean unhealthy. Sometimes a baby born after 40 weeks of pregnancy, can be of low weight , but quite healthy. Good care after birth, good nutrition, attention, love and affection can play a good role in growth of a baby after birth. So, a baby born with low weight can develop a healthy baby in next few months.

During pregnancy fetal growth rate is measured regularly. If the rate is not satisfactory, it is to be checked, whether the mother has any health problem, like high blood pressure, stress etc. By treating it the fetal growth can be improved.