Birth Weight

Newborn babies vary in birth weight and size. Some low birth babies may have health issues. Get the facts on your baby's birth weight.

This content is for informational purposes only. Always consult a healthcare professional.
ⓘ Information

Before we begin: Newborn babies vary in birth weight and size. Some low birth babies may have health issues. Get the facts on your baby’s birth weight.

This tutorial walks you through everything you need to know about birth weight. We explain it in plain language, step by step, so whether you are a student, a patient, or simply curious, you will come away with a solid understanding.

We cover what it is, why it matters, how it is diagnosed, and what you can do about it. Key facts are called out along the way.

What is birth weight? Birth weight is the first weight of your baby, taken just after being born. A low birth weight means that the baby is less than 5 pounds, 8 ounces. A high birth weight means that the baby is more than 8 pounds, 13 ounces.

What can cause low birth weight? A baby with a low birth weight can be born too small, too early (premature), or both. This can happen for many different reasons. They include:

Health problems in the pregnant parent

Taking certain medicines during pregnancy

Substance use during pregnancy

Infections during pregnancy

Being pregnant with multiple babies

Problems with the placenta, the organ that brings oxygen and nutrients to the baby

Having small parents

Genetic conditions in the baby

Birth defects

What problems can low birth weight cause? Babies with low birth weight may be more at risk of certain health problems. They include immediate problems, such as:

Breathing problems

Infections

Hypoglycemia (low blood sugar)

Jaundice

Trouble keeping warm

There is also a higher risk of longer-term problems, including:

Delayed motor and social development

Learning disabilities

Certain health conditions as an adult, such as heart disease, high blood pressure, diabetes, and obesity

What can cause high birth weight? Causes of high birth weight can include:

Having big parents

Diabetes in the pregnant parent

Certain genetic conditions

Too much weight gain during pregnancy

What problems can high birth weight cause? High birth weight can be a concern because it can make delivery of the baby difficult and raise the risk of birth injuries. The baby is at higher risk of problems with:

Blood sugar

Breathing problems

Jaundice

Can birth weight problems be prevented? You may be able to prevent some birth weight problems by:

Getting regular checkups during pregnancy

Getting the right amount of nutrition and calories during pregnancy

Controlling your blood sugar if you have diabetes

Avoiding substance use during pregnancy

Related topics: Large for Gestational Age, Low Birth Weight, Small for Gestational Age.

Categories: Children and Teenagers, Pregnancy and Reproduction.

Source: National Institutes of Health — Eunice Kennedy Shriver National Institute of Child Health and Human Development.

Key Takeaways

Understanding birth weight is an important part of taking charge of your health. Here is what to remember:

  • Know the signs — Recognizing early symptoms can lead to earlier diagnosis and better outcomes.
  • Talk to your provider — If you have concerns or a family history of this condition, bring it up at your next checkup.
  • Stay informed — Medical knowledge evolves. Keep learning and asking questions.
  • You are not alone — Many people deal with this condition. Support groups and educational resources can help.
⚠ Caution
Medical Disclaimer: This information is for educational purposes only. Always consult a healthcare professional for diagnosis and treatment of any medical condition.