Normal Infant Weight

As a parent, you want your infant to be normal, especially in terms of weight. But what exactly is normal infant weight and how does it affect you and your baby? In order to understand normal infant weight, you need to be familiar with birth weight, typical weight development, nutrition and other factors influencing weight.

Birth Weight

• The first time you'll know your infant's weight for sure is at birth, which gives you an indication of whether his weight is normal. According to KidsHealth.org, the majority of full-term babies (those born between 37 and 40 weeks of pregnancy) weigh between 6 pounds 2 ounces and 9 pounds 2 ounces. If your baby weighs less than 5 pounds, 8 ounces, he is considered to be of low birth weight. BabyCenter.com states that birth weight in excess of 9 pounds 15 ounces indicates a condition known as macromosia (a larger than normal baby).

Weight After Birth

• Regardless of other factors, once your baby is born, she will typically lose about 7 to 10 percent of her body weight as she adjusts to life outside of the womb. Most of the weight loss occurs as a result of the loss of extra fluid present in your little one's body at birth, but some loss of weight also takes place as she adapts to the feeding process. KidsHealth.org states that you should expect your baby to regain this weight within approximately 2 weeks of birth.

Factors

• A range of factors affect normal infant weight, including heredity and the mother's health. If either one of a baby's parents has a smaller frame, then the baby is more likely to have the same type of body frame, which would affect her metabolic rate. According to Dr. Sears, tall thin babies are more likely to burn calories more quickly than short plump babies, which results in more gradual weight gain for the longer babies. Your health during your pregnancy also determines in part whether your baby has normal infant weight at birth, since habits such as smoking during pregnancy increase your likelihood of giving birth to a low birth weight baby.

Nutrition

• Normal infant weight for a breastfed baby may be different than normal infant weight for a formula-fed baby. During the first few months, babies gain weight at the same rate, regardless of their food source. However, according to a study conducted by Dr. Katherine Dewey at the University of California at Davis, formula-fed babies tend to gain weight more quickly than breastfed babies between the ages of 4 to 6 months, most likely due to extra water retention and variations in body fat composition. Overall, breastfed babies typically gain about one pound less than formula-fed babies by the age of one year.

Considerations

• Your baby's doctor will monitor his weight at scheduled well-baby checkups and let you know whether your little one's weight is not normal. During these visits, your baby's doctor will chart her weight, comparing it to the weight of other babies that are the same age and gender. Know that it is normal for your baby to go through periods of rapid weight gain (known as growth spurts) and periods of little or no weight gain. However, if you are concerned that your baby is not at a normal weight, then you should discuss your concerns with your baby's doctor.