Average Birth Weight

At the time of childbirth, parents are usually nervous and they generally are eager to know whether the baby is okay, whether the baby has all the fingers and toes and whether the baby has normal weight and length. The newborn is always greeted with such questions from grandpas and grandmas; because length and weight of babies and toddlers are the best indicators of their health.

After birth, a track of weight, length and head size is maintained by the doctors. A healthy baby grows fast and poor growth is considered as a sign of an underlying health problem. It is observed that during first year, newborns grow a big way. Most of the infants triple their birth weight during first year and also increase their length by about 50%. The average birth weight depends on the duration of the pregnancy and on the rate of fetal growth. Premature babies are born with much less than average birth weight and length and so need to be kept at the NICU for a few days. Parents of premature babies should follow a preemie growth chart.

Factors that Determine the Birth Weight of a Baby

The weight of a baby at the time of birth depends on:

• Infant Gender
• Multiple birth factors
• Size of the parents
• Birth order
• Baby's health
• Maternal factors, such as race and ethnicity, nutrition and current and previous pregnancy medical risk characteristics.

Birth Weight of a Baby

• According to the available statistics, the median birth-weight for U.S. singleton, full-term (forty weeks of gestation) births is nearly 3,500 grams (7 pounds, 11 ounces) and about 80% of the newborn infants have birth weight between 6 pounds and 9 pounds 4 ounces (2,750 - 4,250 grams).
• In the developed world, where there is no malnutrition of mothers, where mothers enjoy the benefits of advanced technology, the average birth weight of a full-term newborn is approximately 7 ½ lbs. or 3.2 kg, but is typically in the range of 5.5-10 pounds (2.7-4.6 kg).
• According to the available statistics, the average weight at birth of boys and girls has increased marginally. The average birth weight in the period 1989-1991 was 3,372 grams, compared to 3,434 grams in the period 2004-2006.
• The average total body length of the newborn infants ranges from 14-20 inches (35.6-50.8 cm), although premature newborns may be much smaller. The average length of newborn boys and girls is 50.6 and 50.1cm respectively. Approximately four percent newborn babies are smaller than 46cm.
• Average birth weight for girls and average birth weight for boys is same. But, in general, according to the studies conducted, boys weigh 100 grams more than girls at birth.
• Over 5 percent of newborn babies have a low birth weight, i.e. less than 2,500 grams.
• Approximately 0.08 percent babies have an extremely low birth weight, i.e. less than 1,500 grams.

Birth Weight for Twins

• Forty weeks is the normal duration of a singleton pregnancy. For twins, pregnancy may last for 37 weeks while for a triplet pregnancy, it may last for 34 weeks. Approximately 50% of all multiple births are premature.
• Statistical reports show that the more babies there are, the earlier they could be born. Higher order multiples are always at the risk of prematurity and they generally have a very low birth weight as well.
• Statistical analysis of the data collected during research studies reveal the fact that 58.2% of all multiple birth children were born low birth weight whereas only 6.2% of singletons were born low birth weight.
• The average birth weight of twins is 5 lbs. 5 oz. It is not necessary that the babies born as twins will have same weight. Weight of each baby will be different. Sometimes there can be a difference of 2-3 pounds between the weights of the babies born as twins.

The scientists, all over the world, are researching on the close relationship between average birth weight and the risk of dying within the first year of life. Average birth weight is considered by the researchers as a measure of mortality risk since infants with low birth weight are always at grave risk of mortality. Such infants also have to suffer morbidity (disease) and long-term developmental problems. Genetics, good nutrition, your love, affection and attention in baby care, will play a large part in determining how your baby grows in the years to come. Whether your baby is born large, small, or in between, it doesn't matter. You can always expect your baby to grow fast in the next few months.